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A   HANDBOOK   OF    ANTISEPTICS 


THE  MACMILLAN  COMPANY 

NEW  YORK   •   BOSTON  •    CHICAGO   •   DALLAS 
ATLANTA  •    SAN   FRANCISCO 

MACMILLAN  &  CO.,  Limited 

LONDON  •  BOMBAY  ■  CALCUTTA 
MELBOURNE 

THE  MACMILLAN  CO.  OF  CANADA,  Ltd. 

TORONTO 


A   HANDBOOK 

OF 

ANTISEPTICS 

BY 
HENRY  DRYSDALE  DAKIN,  D.Sc,  F.I.C.,  F.R.S. 

AND 

EDWARD  KELLOGG  DUNHAM,  M.D. 

EMERITUS    PROFESSOR    OF    PATHOLOGY,    UNIVERSITY    AND 

BELLEVUE    HOSPITAL    MEDICAL    COLLEGE 
MAJOR,     MEDICAL    OFFICERS    RESERVE    CORPS,     U.  S.     ARMY 


THE   MACMILLAN    COMPANY 
1918 

All  rights  reserved 


Copyright,  1917, 
By  the  MACMILLAN  COMPANY. 


Set  up  and  electrotyped.     Published  October,  1917. 
Reprinted  with  corrections,  January,  1918. 


NorfajoolJ  ^resg 

J.  S.  Gushing  Co.  —  Berwick  &  Smith  Co. 

Norwood,  Mass.,  U.S.A. 


LOUIS  PASTEUR  JOSEPH  LISTER 

1822-1895  1827-1913 

An  Extract  from   Pasteur's  Address  at  the 
Celebration  of  his  Seventieth   Birthday 

You  lastly,  delegates  of  foreign  nations,  who  have  come 
from  so  far  to  give  proof  of  your  sympathy  with  France  —  you 
bring  me  the  deepest  happiness  which  a  man  can  experience 
who  believes  implicitly  that  science  and  peace  will  triumph 
over  ignorance  and  war,  that  people  will  learn  to  agree  to- 
gether, not  for  purposes  of  destruction  but  for  improvement, 
and  that  the  future  will  belong  to  those  who  shall  have  done 
the  most  for  suiFering  humanity. 

I  address  myself  to  you,  my  dear  Lister,  and  to  all  of  you 
illustrious  representatives  of  Science,  of  Medicine,  and  of 
Surgery. 

Young  people,  young  people,  confine  yourselves  to  those 
methods,  sure  and  powerful,  of  which  we  as  yet  know  only 
the  first  secrets.  And  all,  however  noble  your  career,  never 
permit  yourselves  to  be  overcome  by  scepticism,  both  un- 
worthy and  barren  ;  neither  permit  the  hours  of  sadness  which 
pass  over  a  nation  to  discourage  you.  Live  in  the  serene 
peace  of  your  laboratories  and  your  libraries.  First  ask  your- 
selves. What  have  I  done  for  my  education  ?  then,  as  you 
advance  in  hfe.  What  have  I  done  for  my  country  ?  so  that 
some  day  that  supreme  happiness  may  come  to  you,  the  con- 
sciousness of  having  contributed  in  some  manner  to  the  prog- 
ress and  welfare  of  humanity. 


PREFACE 

The  main  object  of  this  handbook  is  to  give  a  concise 
account  of  the  chief  chemical  antiseptics  which  have  been 
found  useful  for  surgical  purposes  during  the  present  war. 
Some  of  the  publications  on  this  subject  are  not  readily 
accessible  to  many  who  wish  to  inform  themselves  as  to  cur- 
rent European  practice,  and  the  requisite  information  has 
not  yet,  so  far  as  we  know,  been  collected  into  a  form  handy 
for  reference.  It  appeared,  therefore,  that  the  present 
work  might  prove  of  use  to  surgeons  and  others  in  this 
country  who  are  now  taking  up  military  duties  connected 
with  the  care  of  the  wounded. 

The  unparalleled  severity  and  frequency  of  wound  in- 
fections in  the  present  war  has  led  to  considerable  advances 
in  our  knowledge  of  antiseptics  and  of  methods  for  their 
successful  employment.  These  advances  have  already 
proved  to  be  of  great  value  in  the  treatment  of  septic  condi- 
tions in  civil  and  industrial  practice. 

No  endeavor  has  been  made  to  make  a  complete  com- 
pendium of  the  innumerable  antiseptics  and  disinfectants 
that  have  been  proposed  from  time  to  time,  for  text-books 
already  exist  in  which  most  of  these  substances  are  ade- 
quately described,  and  no  good  purpose  would  be  served  by 
duplication.  Our  principal  aim  has  been  to  collect  in  con- 
venient form  the  methods  of  preparation  and  use  of  various 
new  antiseptics  and  modifications  of  old  ones  which  have 
received  some  measure  of  endorsement  by  military  surgeons 
during  the  past  three  years. 

vii 


viii  PREFACE 

The  utility  of  antiseptics,  properly  used  as  adjuncts  to 
efficient  surgery,  is  becoming  more  firmly  established  as  the 
war  proceeds.  Surgeon  General  Sir  George  Makins  in  the 
Hunterian  Oration  for  191 7  says:  "The  most  useful  practi- 
cal test  of  the  efficiency  of  any  method  of  wound  treatment 
is  furnished  by  the  observation  of  the  dates  at  which  micro- 
organisms disappear  from  the  surface  of  the  exposed  tissues 
and  at  which  the  wound  may  be  safely  and  permanently 
closed  by  suture  or  other  means.  When  subjected  to  this 
test  the  antiseptic  method  has  proved  itself  more  rapid  and 
more  trustworthy  than  the  phylacagogic  or  saline  method 
of  treatment." 

A  large  part  of  the  investigations  on  antiseptics  carried  on 
during  the  last  three  years  has  been  done  at  the  instance 
of  the  British  Medical  Research  Committee.  We  are  in- 
debted to  that  Committee  and  to  the  editors  of  the  British 
Medical  Journal  and  the  Journal  of  the  Royal  Army  Med- 
ical Corps  for  permission  to  use  parts  of  the  reports  pub- 
Hshed  in  the  journals  referred  to. 

Purely  surgical  details  concerning  the  use  of  antiseptics 
do  not  He  within  the  scope  of  the  present  book  although  some 
of  the  principles  essential  to  the  successful  use  of  antiseptics 
are  briefly  referred  to.  A  short  statement  of  the  use  of 
antiseptics  in  the  treatment  of  carriers  of  infectious  organ- 
isms is,  however,  included.  Owing  to  similarity  in  the 
substances  used  we  have  deemed  it  advisable  to  include 
a  brief  statement  of  the  use  of  certain  disinfectants  of  the 
chlorine  group  for  the  sterilization  of  drinking  water  and 
the  disinfection  of  hospital  ships. 

September  i,  1917. 

The  Herter  Laboratory 

New  York. 


CONTENTS 


Preface 
Chapter        I. 


Chapter  II. 

Chapter  III. 

Chapter  IV. 

Chapter  V. 

Chapter  VI. 


Vll 


Chapter    VII. 


Chapter  VITI. 


General  Introduction  :  Classification  —  laws  of 
disinfection  —  influence  of  media  —  choice  of 
antiseptics  —  modes  of  application 

Antiseptics  of  the  Chlorine  Group  :  Hypochloroiis 
acid  and  hypochlorites,  eupad,  eusol,  chlora- 
mine-T,  dichloramine-T,  chemical  determina- 
tion of  the  strength  of  chlorine  antiseptics 

The  Phenolic  Group  of  Antiseptics  :  Phenol,  cre- 
sols,  lysol,  thymol,  salicylic  acid,  jS-naphthol, 
picric  acid,  etc 

Salts  of  the  Heavy  Metals  as  Antiseptics  :  Mer- 
cur}^,  silver,  bismuth  and  zinc  salts 

Dyes  as  Antiseptics  :  Malachite  green,  brilliant 
green,  acriflavine,  proflavine    .... 

Miscellaneous  Antiseptics  :  Peroxides,  ozone, 
iodine,  boric  acid  and  salts,  persulphates,  acids, 
alcohol,  ether,  formaldehyde,  hexamethylene- 
tetramine,  iodoform,  permanganates,  quinine, 
chinosol,  acetanilide 

Methods  of  Testing  Antiseptics  :  Lethal  concen- 
trations —  influence  of  media  —  time  relations 

—  velocity  —  results 

Certain  Special  Applications  of  Antiseptics  :  Dis- 
infection of  carriers  —  disinfection  of   water 

—  disinfection    of   hospital  ships,   etc.,   with 
electrolytic  hypochlorite         .... 

ix 


17 


43 


50 


61 


68 


77 


99 


A  HANDBOOK  OF  ANTISEPTICS 

CHAPTER  I 
GENERAL   INTRODUCTION 

The  terms  "antiseptic,"  "disinfectant,"  and  "germicide" 
are  frequently  used  irrespective  of  their  precise  significance. 
Strictly  speaking,  an  antiseptic  is  a  substance  which  inhibits 
the  reproduction  of  microorganisms,  but  it  need  not  of  neces- 
sity manifest  great  killing  or  "germicidal"  action  on  such 
organisms.  Substances  such  as  boric  acid  or  sodium  benzoate 
are  examples  of  compounds  which  are  fairly  effective  in  re- 
straining the  multiplication  of  bacteria  though  possessing 
feeble  germicidal  properties.  Most  of  the  substances  used 
in  the  prevention  of  wound  sepsis  possess  both  antiseptic 
and  germicidal  properties  though  perhaps  they  are  most 
commonly  termed  antiseptics. 

The  term  "  disinfectant "  should  clearly  connote  a  substance 
which  destroys  infecting  agents  and  hence  is  identical  with 
a  germicide,  but  the  word  has  come  to  be  used  in  a  popular 
sense,  irrespective  of  complete  steriUzation,  to  indicate 
some  of  the  phenomena  commonly  associated  with  efficient 
disinfection,  such  as  a  deodorant  effect.^  The  use  of  the 
words  "disinfectant"  and  "disinfection"  in  any  other  sense 
than  that  first  indicated  is  to  be  deprecated. 

^  An  account  of  many  important  hygienic  applications  of  disinfectants  which 
are  beyond  the  scope  of  the  present  work  will  he  found  in  Colonel  Lelean's  book 
on  "Sanitation  in  War."     Churchill.     London. 


2  A  HANDBOOK  OF  ANTISEPTICS 

Classification  or  Antiseptics.  —  For  various  reasons  it 
is  quite  impossible  to  formulate  a  perfectly  logical  classifica- 
tion of  antiseptics.  In  the  first  place,  almost  every  soluble 
substance,  provided  it  can  be  obtained  in  sufficient  concen- 
tration, is  capable  of  exerting  some  antiseptic  action,  so 
that  theoretically  it  would  be  necessary  to  classify  most 
known  organic  and  inorganic  substances,  and  such  an  un- 
dertaking is  obviously  useless  and  unnecessary.  For  prac- 
tical considerations  it  is  sufficient  to  limit  ourselves  to 
those  substances  which  have  found  fairly  extended  use  as 
antiseptics.  In  classifying  these  we  may  endeavor  to  di- 
vide them  according  to  the  nature  of  the  substances  them- 
selves or  according  to  their  mode  of  action.  The  latter 
method  has  much  to  commend  it,  but  unfortunately  we 
know  but  little  of  the  intimate  details  of  the  act  of  disinfec- 
tion as  carried  out  with  even  the  simplest  substances,  such 
as  phenol  or  hydrogen  peroxide. 

Chemical  antiseptics  naturally  fall  into  two  main  classes 
of  compounds  —  inorganic  substances  as  exemplified  by 
bodies  such  as  hydrogen  peroxide,  chlorine,  and  metallic 
salts,  such  as  those  of  mercury  and  silver,  on  the  one  hand, 
and  on  the  other  organic,  or  carbon,  compounds  such  as 
phenols,  aromatic  acids,  dye-stuffs,  such  as  malachite  green, 
etc.,  etc.  But  in  these  two  main  groups  of  inorganic  and 
organic  antiseptics  are  found  substances  of  widely  different 
properties  and  above  all  showing  enormous  variations  in  sia- 
hility.  This  instability  of  some  of  the  most  widely  used  anti- 
septics is  a  point  of  fundamental  importance,  for  upon  a  clear 
recognition  of  this  fact  will  depend,  to  a  considerable  extent, 
success  or  failure  in  their  practical  use.  This  chemical  insta- 
bility is  of  various  kinds,  as  a  few  examples  will  serve  to  show. 

Hydrogen  peroxide  is  a  good  example  of  an  unstable  in- 
organic disinfectant.  The  exact  way  in  which  it  destroys 
microorganisms  is  not  clear  but  is  undoubtedly  connected 
with  its  oxidizing  action.     Now  when  hydrogen  peroxide  is 


GENERAL  INTRODUCTION  3 

placed  on  the  surface  of  an  infected  wound,  it  is  rapidly  de- 
composed, part  of  the  oxygen  of  the  peroxide  being  used  up 
in  oxidizing  organic  compounds  and  much  of  it  being  Jiber- 
ated  as  oxygen  gas  owing  to  the  decomposition  of  the  peroxide 
by  a  widely  distributed  enzyme,  ''catalase."  The  net 
result  is  that  after  a  period  of  time  which  may  be  almost 
incredibly  short  no  undecomposed  hydrogen  peroxide  re- 
mains and  disinfection  proceeds  no  further  towards  comple- 
tion. For,  as  will  be  shown  later,  the  rate  at  which  disinfec- 
tion proceeds  is  directly  related  to  the  concentration  of  the 
antiseptic.  Obviously,  this  instability  indicates  that  hydrogen  • 
peroxide  should  be  either  frequently  renewed  or  restricted  in 
its  use  to  conditions  where  temporary  action  only  is  required. 

The  chlorine  group  of  antiseptics  includes  a  number  of 
important  substances  such  as  ^chlorine  itself,  hjq^ochlorous 
acid  and  its  sodium  and  calcium  salts,  and  organic  "chlor- 
amines"  —  i.e.  substances  containing  chlorine  attached  to 
nitrogen  in  the  form  of  NCI  groups.  They  are  all  char- 
acterized by  marked  instability,  since  in  disinfection  they 
react  not  only  with  the  cell  constituents  of  microorganisms 
but  also  with  most  other  substances  which  are  apt  to  ac- 
company bacteria.  In  so  reacting,  the  active  chlorine  of 
the  antiseptic  is  eventually  converted  either  into  inert  chlo- 
rides or  into  inert  organic  substances  in  which  the  chlorine  has 
Ijecome  united  to  carbon.  Thus  in  using  the  chlorine  anti- 
septics, as  with  hydrogen  peroxide,  the  process  of  disinfec- 
tion will  only  go  on  so  long  as  some  of  the  active  substance 
remains  undecomposed,  and  in  practical  use  means  must  be 
taken  for  the  renewal  of  these  antiseptics  at  suitable  inter- 
vals, in  cases  where  sterilization  is  not  promptly  completed. 

In  the  examples  of  unstable  antiseptics  just  cited,  the 
active  substances  are  decomposed  during  disinfection  and 
cannot  be  regenerated.  In  another  large  class  of  antiseptics 
the  active  agent  is  not  totally  destroyed  during  disinfection 
but  is  rendered  relatively  inactive.     Good  examples  of  this 


4  A   HANDBOOK   OF   ANTISEPTICS 

are  found  among  many  metallic  salts;  mercuric  chloride 
and  silver  nitrate,  for  example,  are  much  less  effective  when 
acting  on  bacteria  suspended  in  hard  water  than  when  acting 
on  washed  bacteria  suspended  in  distilled  water.  Similarly, 
phosphates  and  other  salts  frequently  found  in  wound  exu- 
dates inhibit  the  action  of  metallic  antiseptics.  In  these 
cases  disinfection  by  the  metallic  salts  is  impeded  not  by 
the  complete  destruction  of  the  compound,  as  with  hydrogen 
peroxide  or  chlorine  antiseptics,  but  through  the  conversion 
of  the  metallic  salt  into  an  inactive  form.  This  conversion 
may  be  effected  either  by  precipitation  of  the  metallic  com- 
ponent in  an  insoluble  form,  or  by  changing  its  state  —  e.g. 
changing  its  condition  of  ionization  in  aqueous  solution.  In 
such  cases  the  antiseptic  substance  is  rendered  inert  but  not 
destroyed  and,  theoretically  at  least,  could  be  regenerated 
by  suitable  chemical  means. 

Lastly,  there  are  other  substances  used  as  antiseptics  which 
apparently  are  stable  during  disinfection  or  at  least  com- 
paratively so.  Familiar  examples  of  compounds  of  this 
type  are  found  in  the  phenols  and  in  aromatic  substances  of 
the  dye  class.  These  compounds  apparently  are  not  readily 
decomposed  by  the  cell  constituents  of  bacteria  nor  by 
most  substances  which  are  apt  to  accompany  the  latter. 
It  has  been  suggested  that  some  of  these  antiseptics  act  by 
virtue  of  changes  they  produce  in  the  surface  layer  of  the 
bacterium  so  that  the  latter  is  rendered  permeable  by  the 
antiseptic.  But  even  with  these  relatively  stable  substances 
there  is  a  definite  limit  to  the  amount  of  disinfection  which 
any  given  quantity  of  the  compound  can  accomplish  and 
this  amount  will  vary  according  to  the  conditions  under 
which  the  antiseptic  acts.  This  fact  will  be  noted  again 
in  the  following  section  in  which  some  reference  is  made  to 
the  laws  governing  disinfection. 

The  following  table  shows  the  relative  stability  or  insta- 
bility of  some  of  the  common  groups  of  antiseptics : 


GENERAL   IN  TROD  UC  TION 


Inorganic  Antiseptics 


Unstable,    easily    decomposed    during 

disinfection 
Unstable,    easily    decomposed    during 

disinfection 
Unstable,    easily    decomposed    during 

disinfection 
Less  unstable  than  chlorine 
Stable 
Often  inactivated  by  precipitation  or 

otherwise 
Often  inactivated  by  precipitation  or 

otherwise 
Often  inactivated  by  precipitation  or 

otherwise 
Often  inactivated  by  precipitation  or 

otherwise 

Antiseptics 

Stable 

Fairly  stable 
Unstable 
Mostly  stable 

Mostly  stable 

Unstable,  easily  decomposed  during 
disinfection 

Mostly  stable,  though  sometimes  re- 
duced to  leuco-forrns,  and  often 
adsorbed  by  tissues 

It  is  a  surprising  fact  that  this  varying  stability  of  anti- 
septics is  so  Httle  reaHzed  by  many  workers.  Current  Utera- 
ture  is  full  of  reports  of  experiments  in  which  bacteriologists 
have  added  reactive  unstable  substances,  such  as  hypo- 
chlorous  acid,  to  media  which  cause  their  prompt  disap- 
pearance in  dilute  solution ;  the  mixture  containing  little  or 
no  remaining  antiseptic  is  subsequently  sown  with  organ- 
isms and  astonishment  is  expressed  at  the  inefficiency  of  the 
substance  employed  as  a  disinfectant.  This  important  point 
will  be  referred  to  repeatedly  in  later  sections. 

The  Laws  Governing  Disinfection.  —  These  have  been 
chiefly  worked  at  by  Miss  Chick. ^  Earlier  experiments  were 
^  Journal  of  Hygiene,  8,  p.  92,  1908,  and  10,  p.  238,  1910. 


Hydrogen  Peroxide  and  some  of  its 

derivatives 
Chlorine 

HjTJochlorous  Acid  and  its  Salts 

Bromine  and  Iodine 
Boric  Acid  and  its  Salts 
Mercury  Salts 

Silver  Salts 

Bismuth  Salts 

Zinc  Salts 


Organic 

Alcohol,  Ether,  etc. 
Iodoform 
Formaldehyde 

Hexamethylenetetramine  and  its  de- 
rivatives 
Phenols,  Naphthols,  and  derivatives 
Aromatic  Chloramines 


Dyes  such  as  malachite  green, 
flavine,  etc. 


acn- 


6  A   HANDBOOK   OF   ANTISEPTICS 

carried  out  by  Kronig  and  PauF  and  by  Madsen  and  Nyman.'^ 
It  would  be  out  of  place  to  go  into  the  details  of  the  elaborate 
experiments  and  calculations  necessary  to  elucidate  the 
principles  of  disinfection  but  a  brief  summary  of  the  essential 
results  may  be  given.  Miss  Chick  observed  the  number  of 
bacteria  that  survived,  at  varying  intervals  of  time,  the 
action  of  a  constant  quantity  of  a  stable  antiseptic,  such  as 
phenol,  at  a  constant  temperature,  on  a  known  number  of 
organisms.  By  utilizing  these  results  mathematically  she 
was  able  to  calculate  a  velocity  coefficient  for  the  disinfecting 
action  of  the  substance.  The  main  result  of  these  experi- 
ments was  to  show  that  in  ah  essential  particulars  the  act 
of  disinfection  could  be  regarded  as  obeying  the  laws  govern- 
ing a  simple  chemical  reaction,  the  disinfectant  representing 
one  reagent  and  the  bacteria  the  other.  This  conception  is 
of  the  greatest  importance  since  the  cardinal  points  of 
efficient  disinfection,  namely  adequate  active  mass  or  con- 
centration of  antiseptic,  time  of  action,  and  perfect  contact, 
are  thereby  experimentally  established. 

The  influence  of  temperature  upon  the  rate  of  disinfection 
is  interesting  since  here  again  a  close  analogy  exists  be- 
tween ordinary  chemical  reactions  and  disinfection.  The 
velocity  of  disinfection  increases  with  rise  in  temperature  in 
a  manner  similar  to  that  of  an  ordinary  chemical  reaction. 
Some  idea  of  the  magnitude  of  the  effect  of  temperature 
may  be  gathered  from  the  fact  that  with  metallic  salts  the 
mean  velocity  of  disinfection  increased  2-4  fold  for  a  rise 
in  temperature  of  10°  C,  while  with  phenol  it  was  as  high  as 
eightfold,  using  B.  paratyphosus  as  test  organism  in  each  case. 

It  must  be  remembered,  however,  that  the  similarity  in 
the  mathematical  relations  governing  the  velocity  of  simple 
chemical  reactions  and  disinfection  does  not  of  necessity  prove 
that  the  act  of  disinfection  is  a  chemical  one,  although  with 
some  antiseptics  this  is  almost  certainly  the  case. 

1  Zeitschr.  f.  Hygiene,  25,  p.  i,  1897.  2  /^.^  ^^^  p.  388,  1907. 


GENERAL   INTRODUCTION  7 

Influence  or  Media.  —  The  capacity  of  a  disinfectant 
to  kill  microorganisms  is  dependent  to  an  extraordinary  de- 
gree upon  the  conditions  under  which  it  acts.  Almost  in- 
variably the  greatest  germicidal  activity  is  shown  when  the 
substance  acts  upon  bacteria  freed  from  contaminating  cul- 
ture media  and  suspended  in  distilled  water  or  salt  solution. 
The  presence  of  proteins  and  similar  substances,  e.g.  peptones, 
usually  causes  a  huge  reduction  in  the  germicidal  activity 
of  most  substances.  In  the  presence  of  pus,  in  which  many 
of  the  organisms  are  partly  ingested  in  the  bodies  of  the 
dead  leucocytes  and  hence  difficult  to  attack,  the  results  are 
still  less  favorable.  The  following  table  gives  some  idea 
of  the  reduction  in  germicidal  activity  of  some  of  the  common 
antiseptics  acting  for  two  hours  at  room  temperature  on 
staphylococcus  aureus  (i  drop  of  24  hours  broth  culture)  in 
a  total  volume  of  5  cc.  of  either  water  or  50  per  cent  horse 
serum.  The  antiseptics  were  in  all  cases  added  last  of  all 
to  the  mixtures : 


Antiseptic 


Phenol       .... 
Salicylic  Acid      .     . 
Hydrogen  Peroxide 
Iodine        .... 

Mercuric  Chloride  ^ 
Silver  Nitrate  1    .     . 
Sodium  Hypochlorite 
Chloramine-T      .    . 


Si 

'APHYLOCOCCI 

Staphylococci  in  50% 

IN  Water 

Horse  Serum 

250  - 

1:50  - 

500  + 

I : 100  + 

2500  - 

I : 100  — 

5000  + 

1 :  250  + 

3500  - 

1 :  1700  — 

8000  + 

1 :  2000  + 

100,000  — 

1 :  1000  — 

1,000,000  + 

I  :  2500  + 

5,000,000  — 

I  :  25,000  — 

10,000,000  + 

I  :  50,000  + 

1,000,000  — 

I  :  10,000  — 

10,000,000  -\- 

I  :  25,000  + 

500,000  — 

I  :  1500  - 

1,000,000  + 

I  :  2000  + 

500,000  — 

1 :  2000  — 

1,000,000  + 

I  :  3000  + 

The  -  sign  indicates  sterilization  as  evidenced  by  negative  subcultures. 
while  the  +  sign  indicates  incomplete  disinfection. 

1  No  antidote  was  used  in  these  experiments  to  prevent  the  action  of  traces  of 
the  salt  in  the  subcultures.     (Cp.  p.  52.) 


8  A   HANDBOOK   OF   ANTISEPTICS 

In  order  to  illustrate  the  difficulty-  of  sterilizing  pus,  some 
selected  experiments  made  by  W.  Parry  Morgan  ^  may  be 
cited.  In  these  experiments  one  part  of  pus  was  mixed  with 
nine  parts  of  antiseptic  and  after  ten  minutes  lo  cmm.  were 
planted  in  liquid  agar  which  was  then  shaken  and  incubated. 
It  was  found  that  when  the  antiseptic  was  strong  the  num- 
ber of  colonies  could  be  counted  readily,  but  when  it  was 
weak  the  agar  became  opaque  with  innumerable  colonies. 
The  results  are,  of  course,  comparative  and  do  not  lend 
themselves  to  strict  quantitative  expression,  for  the  specimens 
of  pus  vary  much  among  themselves. 

Table  showing  the  Effects  of  Antiseptics  upon  the  Growth 
OF  Bacteria  in  Pus 

Iodine        i :  400  i :  800  i :  1600  i :  3200 

16  hours +  ++  +  +  ++  +  + 

Mercury  Biniodide i :  400  i :  800  i :  1600  i :  3200 

16  hours +  ++  +++  +  + 

Phenol 1 :  40  i :  80  i :  160 

16  hours      . +  ++  +  +  + 

Sodium  Hypochlorite i :  200  i :  400  i :  800  i :  1600 

(Dakin's  Solution) 

18  hours —  —  —              + 

3  days —  —  —              + 

Eusol 

(Bleaching  Powder  and  Boric  Acid) 

available  chlorine i :  200  i :  400  i :  800  i :  1600 

18  hours —  —  —              + 

3  days —  —  —              +  + 

When  the  proportion  of  pus  to  antiseptic  was  higher  than  in 
the  above  experiments,  the  disinfecting  action  was  still  fur- 
ther diminished. 

A  few  substances,  such  as  some  derivatives  of  hexameth- 
ylenetetramine,  are  known  whose  germicidal  action  is  said 
not  to  be  materially  affected  by  the  presence  of  serum,  and 
one  striking  example  exists  of  a  substance  which  is  apparently 
actually  more  active  in  serum  than  in  water.  This  compound 
prepared  by  Benda  and  termed  trypaflavine  but  now  known 

1  Brit.  Med.  Journ.,  May  13,  1916. 


GENERAL   INTRODUCTION  9 

as  acriflavine  (sometimes  simply  flavine)  has  been  showni  by 
Browning  ^  and  his  colleagues  to  kill  staphylococci  in  serum 
at  one  tenth  the  concentration  necessary  when  the  same  or- 
ganisms are  suspended  in  peptone  solution.  Experiments 
with  pus,  however,  showed  much  higher  concentrations  were 
necessary  to  achieve  sterilization  than  with  peptone  or  serum 
media. 

The  causes  of  these  huge  variations  in  the  germicidal  ac- 
tion of  antiseptics  under  various  conditions  are  but  slightly 
understood.  The  reduction  in  the  case  of  members  of  the 
chlorine  group  can  be  accounted  for  to  a  considerable  extent 
by  the  rapidity  of  the  chemical  interaction  of  the  disinfectant 
with  the  protein  medium,  with  the  production  of  inert 
substances  if  the  proteins  be  in  sufficient  excess.  But  other 
causes  must  be  at  work  where  the  more  stable  antiseptics 
such  as  phenol  and  the  dye-stuffs  are  concerned.  It  is 
frequently  said  that  the  antiseptic  is  "  quenched  "  or  "  fixed  " 
by  the  protein  medium,  but  these  terms  do  not  carry  much 
enHghtenment,  nor  does  the  suggestion  that  the  molecular 
condition  of  the  antiseptic  is  influenced  by  the  presence  of 
colloids  in  the  medium.  The  low  germicidal  action  shown  by 
most  antiseptics  against  pus  is  due  in  part  no  doubt  to  the 
mechanical  difficulties  of  penetrating  the  mucoid  particles 
in  the  pus.  Parry  Morgan  has  shown,  moreover,  that  when 
the  organisms  in  pus,  or  added  to  it,  have  undergone  phago- 
cytosis they  are  less  readily  destroyed  by  antiseptics.  The 
reduction  in  antiseptic  activity  of  a  substance  in  the  presence 
of  any  particulate  matter  has  been  often  observed  ^  and  is 
probably  connected  with  the  surface  adsorption  of  the  anti- 
septic by  the  particles  with  consequent  reduction  in  its  ef- 
fective concentration. 

The  Choice  of  Antiseptics.  —  The   selection  of  anti- 
septics for  various  purposes  requires  the  consideration  of  a 

1  Brit.  MccJ.  Journ.,  Jan.  20,  1917. 

2  Chick,  and  Martin,  Journ.  of  Hygiene,  8,  p.  C54,  1908. 


10  A   HANDBOOK   OF   ANTISEPTICS 

number  of  factors.  The  possession  of  high  germicidal  ac- 
tivity, as  ordinarily  tested  in  the  presence  of  media  comparable 
with  those  in  which  the  disinfectant  is  to  act,  is  of  course 
desirable.  But  it  is  equally  important  to  bear  in  mind  the 
concentration  at  which  the  substance  may  be  used,  for  a 
relatively  innocuous  substance  used  in  fairly  high  concentra- 
tion will  often  give  much  more  satisfactory  results  than  lower 
concentrations  of  more  active  substances.  The  speed  of 
disinfection  is  also  an  important  .question  for  it  varies  enor- 
mously with  different  types  of  antiseptics.  Antiseptics  of 
the  chlorine  group  and  iodine  are  among  the  most  rapid, 
while  the  dyes  and  some  metallic  salts  are  relatively  slow. 
An  inspection  of  the  tables  in  Chapter  VII,  in  which  a  heavily 
infected  mixture  of  blood  serum  and  muscle  extract  was 
treated  with  various  antiseptics  at  about  the  concentration 
recommended  for  wound  treatment  will  give  a  good  idea  of 
their  relative  speed  of  action  and  potency  under  the  conditions 
selected. 

The  ideal  surgical  antiseptic  should  effect  complete  steri- 
lization within  its  sphere  of  action  without  causing  any 
damage  to  animal  cells.  At  the  moment  such  a  substance 
does  not  appear  likely  to  be  found,  but  on  the  other  hand 
it  is  surprising  to  see  how  little  damage  may  be  done  to 
animal  tissues  by  some  active  antiseptics.  An  important 
method  of  judging  of  the  injurious  action  of  antiseptics  is  to 
investigate  the  condition  of  the  leucocytes  in  wounds  re- 
cently treated  with  the  substance  under  consideration.  In 
general  it  appears  from  experiments  in  vitro  that,  with  the 
strength  of  antiseptics  commonly  used  in  surgery,  mercury 
salts  and  h3^och]orites  have  relatively  httle  effect  on  phago- 
cytosis as  compared  with  phenol  (Parry  Morgan).  It  is  a 
regular  phenomenon  to  observe  activity  of  the  leucocytes 
obtained  from  wounds  which  have  been  recently  treated 
with  hypochlorites. 

Ingenious  methods  for  determining  the  influence  in  vivo 


GENERAL   INTRODUCTION  11 

of  antiseptics  on  the  activities  of  leucocytes  have  been  worked 
out  by  Col  C.  J.  Bond.i  Indigo  impregnated  threads  are 
laid  in  aseptic  or  septic  wounds  with  or  without  antiseptics. 
After  varying  periods  of  time  the  threads  will  be  found  to 
have  become  decolorized  owing  to  the  ingestion  of  pig- 
ment particles  by  the  leucocytes.  It  was  found  that  the 
application  of  a  strong  antiseptic,  e.g.  i :  looo  mercury 
biniodide  or  i :  20  phenol,  to  a  wound  such  as  that  made  for 
the  radical  cure  of  hernia  or  for  the  removal  of  varicose  veins, 
does  delay  to  some  shght  extent  the  decolorization  of  an 
indigo  thread  placed  in  it  as  a  drain.  But  in  general  it  ap- 
peared that  antiseptic  solutions  in  moderate  concentration 
exercise  less  influence  over  emigration  and  phagocytosis  than 
many  surgeons  had  supposed.  There  are,  however,  rea- 
sons for  concluding  that  many  antiseptics  do  exert  a  con- 
siderable inhibitive  effect  on  the  return  immigration  of  liv- 
ing phagocytes.  But  if  the  use  of  antiseptics  does  bring 
about  a  reduction  of  the  numbers,  or  inhibit  the  activities, 
of  pathogenic  organisms,  not  merely  in  vitro  but  in  the 
actual  wound,  then  although  these  reagents  undoubtedly  do 
cause  the  death  of  a  certain  number  of  body  cells  and  prevent 
others  from  again  reaching  the  tissues,  this  is  relatively 
of  slight  importance  if  the  invading  organisms  are  at  the 
same  time  materially  diminished  in  numbers  or  offensive 
capacity. 

Other  criteria  which  need  consideration  in  judging  of  the 
suitability  of  any  particular  substance  as  an  antiseptic  con- 
cern the  absence  of  marked  irritation  of  the  skin  or  other  tis- 
sues to  which  the  substance  may  be  applied,  and  also  its 
effect  on  the  rate  of  dissolution  of  necrotic  tissue  and  the 
rate  of  formation  of  healthy  granulations.  In  general,  too, 
it  will  be  found  that  antiseptics  which  coagulate  the  proteins 
in  wound  exudates,  e.g.  salicylic  acid,  or  strong  phenol,  are 
less  desirable  than  those  which  do   not   act   in   this  way, 

1  Brit.  Med.  Journ.,  June  3,  1916,  Feb.  3,  1917. 


12  A   HANDBOOK  OF   ANTISEPTICS 

since  anaerobes  are  apt  to  multiply  in  necrotic  tissue  more  or 
less  surrounded  with  impermeable  coagulum.  In  contrast 
with  this  effect,  the  solvent  action  of  hypochlorites  and  the 
related  dichloramine-T  on  dead  tissue  is  marked  and  con- 
stitutes a  valuable  property. 

But  the  problem  of  selecting  the  most  desirable  antiseptic 
is  by  no  means  limited  to  the  preceding  considerations. 
It  is  of  paramount  importance  that  judgment  should  be 
exercised  in  choosing  a  substance  which  is  likely  to  be  effec- 
tive under  the  conditions  of  its  employment.  Thus  any  of 
the  hypochlorite  solutions  which  give  excellent  results  when 
used  for  the  intermittent  flushing  of  infected  wounds,  partly 
on  account  of  the  rapidity  of  their  action  and  of  their  gen- 
erally inoffensive  character,  are  almost  useless  when  ap- 
plied in  small  amounts  as  a  simple  wet  dressing  which  is 
infrequently  renewed.  In  the  latter  case  no  active  anti- 
septic persists  for  any  significant  length  of  time  and  not  much 
more  is  accomplished  than  the  prevention  of  secondary  rein- 
fection. When  prolonged  action  is  required  and  frequent 
application  is  impossible,  recourse  must  be  had  to  more 
stable  mixtures  which  yield  up  their  store  of  antiseptic  slowly. 
Examples  of  such  substances  are  the  bismuth  iodoform  par- 
affin mixture  (B.I.P.)  and  the  oily  solution  of  dichloramine- 
T.     These  substances  will  be  referred  to  later. 

Finally,  it  must  be  once  more  emphasized  that  antiseptics 
at  best  are  only  accessories  to,  and  not  substitutes  for,  efficient 
surgical  treatment  of  infected  wounds.  The  disinfecting 
action  of  antiseptics  is  practically  restricted  to  the  wound 
surfaces  and  the  cavity  inclosed  by  them  and  none  of  them 
appears  to  have  any  considerable  power  of  penetration  with- 
out simultaneous  loss  of  activity.  The  prompt  excision  of 
damaged  tissue  has  now  become  a  routine  method  in  war 
surgery  on  the  Western  Front,  and  this  procedure  renders 
the  effective  employment  of  antiseptics  much  more  certain 
than  it  was  earlier  in  the  war. 


GENERAL   INTRODUCTION  13 

Modes  of  Application.  —  Antiseptics  are  applied  in 
various  ways,  according  to  the  character  of  the  wound,  the 
nature  of  the  substance,  and  the  kind  of  action  desired. 
Aqueous  solutions  are  used  most  extensively.  When  un- 
stable antiseptics,  such  as  hypochlorites  and  chloramine-T, 
are  used  and  prolonged  antiseptic  action  is  required  —  as 
in  the  treatment  of  freshly  infected  or  septic  wounds  —  it  is 
necessary  to  employ  some  rneans  of  frequently  renewing  the 
antiseptic.  This  end  is  commonly  accomplished  either  by 
irrigation  or  by  intermittent  instillation  of  fresh  antiseptic 
solution  into  the  wound  by  means  of  short  rubber  tubes  so 
arranged  that  the  solution  may  reach  every  recess  of  the 
wound.  This  method  has  been  used  extensively  in  the  pres- 
ent war  and  has  given  excellent  results.  The  technique  of 
the  method  will  be  found  fully  described  in  a  book  by  Carrel 
and  Dehelly.^  To  obtain  the  best  results  with  this  mode  of 
treatment,  a  careful  observation  of  details  is  essential,  and 
as  only  an  outline  can  be  given  here  reference  should  be 
made  to  the  book  just  mentioned  or  to  numerous  original 
papers  in  recent  publications. 

The  first  step  is  the  mechanical  cleansing  of  the  wound 
by  excision,  this  being  omitted  as  dangerous  if  the  phenomena 
of  inflammation  have  already  set  in.  The  wound  is  then 
subjected  to  active  antiseptic  treatment.  For  this  purpose 
sodium  hypochlorite  —  so-called  Dakin's  solution  —  is  em- 
ployed at  a  concentration  of  0.5  per  cent  (see  page  23). 
Great  care  is  taken  to  insure  uniform  distribution  of 
the  antiseptic  by  means  of  the  rubber  tubes  which  are 
usually  of  fine  bore,  closed  at  one  end  and  provided 
near  the  closed  end  with  a  number  of  fine  lateral  per- 
forations. A  number  of  these  tubes,  depending  on  the 
size  of  the  cavity,  are  disposed  within  the  wound,  care  being 
taken  that  no  gauze  intervenes  between  the  tubes  and  the 

*  Le  traitement  des  plaies  infectes,  Collection  Horizon,  Masson  et  Cie., 
Paris,  1917. 


14  A   HANDBOOK   OF   ANTISEPTICS 

tissues  and  also  that  the  tubes  are  not  so  closely  applied 
as  to  block  the  perforations.  The  tubes  are  led  through  the 
outer  dressing  and  kept  in  position  with  safety  pins.  When, 
as  is  always  the  case  with  large  wounds,  more  antiseptic 
solution  is  needed  than  can  be  conveniently  supplied  by  using 
a  glass  syringe,  the  ends  of  the  tubes  are  connected  by  T 
pieces  to  a  single  tube  which  in  turn  connects  with  a  glass 
reservoir  holding  a  liter  of  solution  which  is  suspended  sev- 
eral feet  above  the  level  of  the  bed.  The  supply  of  solution 
to  the  wound  is  arranged  by  opening  for  a  few  seconds 
every  two  hours  the  clip  attached  to  the  main  tube.  An 
important  point  is  the  absence  of  a  drainage  opening  at  the 
most  dependent  part  of  the  wound;  in  fact,  the  ideal  ar- 
rangement is  attained  when  the  wound  is  cup-shaped; 
when  it  is  on  the  inferior  surface  of  a  limb  the  aperture  is 
partly  plugged  with  gauze  to  hinder  free  escape  of  the  fluid. 
It  is  important  to  note  that  vessels  in  the  base  of  the  wound 
should  not  be  ligatured  with  silk  since  this  material  is  at- 
tacked by  hypochlorites.  The  routine  bacteriological  ex- 
amination of  the  wound  is  important.  It  is  found  that  when 
practical  sterility  has  been  maintained  for  two  or  three 
days  it  is  safe  to  close  the  wound.  In  the  case  of  wounds 
that  have  suppurated,  it  is  advisable  to  wait  a  little  longer. 

In  place  of  the  hypochlorite,  the  more  stable  chloramine- 
T  has  been  used  to  a  considerable  extent  and  with  particular 
success  in  fresh  industrial  accidents.  It  is  usually  used  in 
0.5-2  per  cent  solution  and  its  action  is  similar  to  that  of 
h3rpochlorite  save  that  necrotic  tissue  is  less  rapidly  removed. 

The  methods  of  application  of  the  ordinary  solutions  of 
less  unstable  antiseptics  such  as  phenol,  iodine,  and  the 
metallic  salts,  call  for  no  special  comment. 

When  the  frequent  renewal  of  the  antiseptic  is  impracti- 
cable or  not  desired,  recourse  may  be  had  to  pastes  or 
oils  of  various  kinds,  which  embody  a  store  of  antiseptic 
that  may  be  gradually  utilized.    The  mild  antiseptic  action 


GENERAL  INTRODUCTION  15 

of  a  paste  containing  about  one  per  cent  of  chloramine-T 
and  five  per  cent  of  sodium  stearate  in  water  is  often 
useful  to  maintain  sterility  and  prevent  reinfection  of 
wounds  which  have  previously  received  more  vigorous 
treatment.  A  much  more  intensive  action  can  be  obtained 
from  the  use  of  dichloramine-T  dissolved  in  eucalyptol 
and  paraffin  as  described  on  page  39.  The  amount  of 
active  antiseptic  which  may  thus  be  applied  to  the  wound 
surface  is  extremely  large  and  its  action  is  correspondingly 
prolonged.  The  method  of  using  this  oil  is  particularly 
simple  and  the  results  appear  to  be  exceptionally  good, 
both  as  regards  the  prevention  and  treatment  of  sepsis. 

A  paste  possessing  moderate  potency,  introduced  by 
Rutherford  Morison,  composed  of  bismuth  subnitrate, 
iodoform,  and  paraffin,  is  being  widely  used  with  good  results 
both  for  wounds  of  the  soft  tissues  and  for  fractures.  The 
fact  that  the  wounds  do  not  need  dressing  for  several  days 
gives  it  a  great  advantage  when  the  number  of  cases  re- 
quiring treatment  is  very  large,  and  because  of  this  it  also 
secures  a  maximum  of  rest  for  the  wound. 

It  must  not  be  forgotten  that  the  employment  of  pastes 
as  a  primary  dressing  is  not'  free  from  serious  risks  and 
should  only  be  practiced  with  caution.  The  use  of  salicylic 
acid  pastes  for  the  immediate  treatment  of  wounds  other 
than  superficial  ones  is  said  to  have  given  particularly  poor 
results  as  anaerobes  are  apt  to  flourish  in  walled  off  recesses 
of  the  wound.  The  coagulating  properties  of  sahcylic  acid 
would  especially  facilitate  such  a  result. 

The  administration  of  antiseptics  by  intravenous  injection 
is  the  only  method  other  than  that  of  local  application  that 
is  at  all  practiced  for  military  purposes.  Eusol  has  been 
used  to  some  extent  for  this  purpose  ^  though  it  is  abundantly 
clear  that  any  action  it  may  have  is  unconnected  with  any 

1  Lorrain  Smith,  Ritchie,  and  Rettie,  Brit.  Med.  Journ.,  Nov.  13,  191 S-  Frazer 
and  Bates,  Brit.  Med.  Journ.,  Aug.  5,  1916. 


16  A   HANDBOOK   OF   ANTISEPTICS 

germicidal  effect  since  the  actively  haemolytic  hypochlorite, 
in  therapeutic  doses,  is  immediately  decomposed  by  the 
blood.^  A  few  striking  cases  of  favorable  results  of  its  use 
have  been  recorded  but  as  the  procedure  has  not  found  wide 
acceptance  and  is  not  free  from  danger,  it  is  well  to  suspend 
judgment  as  to  its  value.  A  number  of  years  ago  ^  silver 
nitrate  was  used  intravenously  in  the  same  way  and  while  it 
was  clear  that  no  direct  germicidal  effect  was  possible,  some 
kind  of  beneficial  effect  was  believed  to  follow  the  haemolysis 
caused  by  the  silver  salt. 

1  Dakin,  Brit.  Med.  Journ.,  June  17,  1916. 

2  Klinisch-Therapeutische  Wochenschrift,  No.  ^2,  p.  881,  1908, 


CHAPTER  II 
ANTISEPTICS   OF  THE   CHLORINE   GROUP 

In  the  present  war,  which  is  distinguished  by  the  frequency 
and  intensity  of  virulent  wound  infections,  no  class  of  anti- 
septics has  received  such  extensive  employment  as  those  of 
the  chlorine  group.  When  properly  applied  —  and  this  is 
an  important  reservation  —  it  is  generally  conceded  that 
they  have  proved  of  genuine  value  to  the  surgeon.  All  of 
the  antiseptics  of  this  group  are  characterized  by  chemical 
instability  in  the  presence  of  organic  matter,  and  therefore 
conditions  favorable  for  their  use  must  include  either  pro- 
vision for  their  frequent  renewal,  or  the  use  of  some  im- 
miscible solvent  for  the  antiseptic  so  that  the  active  compound 
may  be  gradually  liberated. 

The  members  of  the  group  under  consideration  are  often 
spoken  of  as  containing  "active"  chlorine  as  distinct  from 
inert  chlorine  such  as  that  in  common  salt.  It  must  not  be 
inferred,  however,  that  the  phrase  "active  chlorine"  neces- 
sarily implies  either  that  free  chlorine  is  contained  in  the 
substance  or  is  liberated  from  it,  as  more  often  it  will  be 
found  that  hypochlorous  acid  or  some  such  compound  is 
the  active  agent.  From  the  standpoint  of  disinfection,  it 
is  probably  correct  to  connote  with  the  term  "active  chlorine  " 
in  a  compound,  the  ability  of  any  particular  substance  to 
part  with  chlorine,  free  or  combined,  in  such  a  way  that  it 
can  effect  the  chlorination  of  bacterial  and  other  proteins.^ 

>/  1  All  compounds  containing  active  chlorine  possess  the  property  of  liberating 
iodine  from  an  acidified  solution  of  potassium  iodide.  The  iodine  may  be  de- 
tected by  the  development  of  a  blue  color  on  adding  starch  paste.  This  reaction 
will  often  be  found  useful  in  testing  for  the  presence  of  unchanged  antiseptic. 

c  17 


18  A   HANDBOOK   OF   ANTISEPTICS 

This  chlorination  of  bacterial  protein  seems  to  be  incompatible 
with  the  life  of  the  microorganism.  It  is  necessary  to  refer 
in  outline  to  the  nature  of  this  reaction.  All  proteins,  irre- 
spective of  their  origin,  contain  large  numbers  of  amino-acid 
groups,  which  may  be  represented  as  shown  below :   (I) 

H  H 

R— C— CO  R— C— CO— ' 

I  I 

NH  NCI 


I  II 

These  groups  are  capable  of  attack  by  substances  containing 
active  chlorine  in  such  a  way  that  the  hydrogen  attached  to 
the  nitrogen  atom  is  replaced  by  chlorine  (II).  The  com- 
pounds thus  formed  contain  the  (NCI)  group  and  hence 
belong  to  the  class  of  chloramines.  Their  chlorine  is  still 
active  and  they  are  themselves  active  germicides.  Other 
concomitant  reactions  also  occur  which  use  up  part  of  the 
chlorine,  converting  it  into  an  inert  form,  e.g.  the  chlorine 
becomes  united  to  carbon  or  forms  chlorides. 

This  formation  of  germicidally  active  chloramines  is  of 
importance  in  several  respects.  For  example,  the  proteins 
and  other  nitrogenous  compounds  present  in  wound  secre- 
tions may  be  converted  into  chlorine  derivatives  of  antiseptic 
value  by  the  action  of  a  sufficient  quantity  of  hypochlorite 
or  similar  substance.^    While  preformed  chlorine  derivatives 

1  It  is  of  interest  to  note  that  while  chlorine,  bromine,  and  iodine  have  not 
widely  differing  germicidal  properties,  hypobromites  and  hypoiodites  in  contrast 
to  hypochlorites  have  but  trivial  disinfecting  action.  Correlated  with  this  fact 
is  the  observation  that  hypochlorites  react  readily  with  proteins  while  hypo- 
bromites and  hypoiodites  do  not.  On  the  other  hand,  certain  synthetic  broma- 
mines  which  react  readily  with  amino-acids  and  proteins  have  a  high  germicidal 
potency.  The  ability  to  react  with  proteins  and  allied  bodies  is  clearly  associated 
with  germicidal  activity  in  members  of  the  halogen  group  of  antiseptics. 


ANTISEPTICS   OF   THE   CHLORINE   GROUP  19 

prepared  from  proteins  are  powerful  germicides,  they  are 
not  convenient  substances  for  general  use,  but  by  using 
other  types  of  nitrogen  compounds  for  chlorinating,  synthetic 
chloramines,  with  valuable  antiseptic  properties,  are  readily 
obtainable. 

For  detailed  information  concerning  the  action  of  chlorine 
antiseptics  upon  amino-acids,  proteins,  etc.,  as  well  as  the 
preparation  of  many  synthetic  chloramines,  reference  must 
be  made  to  the  original  papers.^ 

In  addition  to  their  disinfecting  action,  the  chlorine 
antiseptics  are  strong  oxidizing  agents  and  deodorants  and 
moreover  possess  in  high  degree  the  property  of  decompos- 
ing toxins.  By  the  regulated  action  of  hypochlorous  acid, 
Dean  ^  has  prepared  a  non-toxic  dysentery  vaccine  and  it 
is  a  common  observation  that  the  free  use  of  hypochlorites 
may  reduce  the  constitutional  symptoms  arising  from  septic 
processes  and  that  they  reappear  on  discontinuing  the  anti- 
septic treatment. 

The  antiseptics  of  the  chlorine  group  which  are  most  com- 
monly employed  in  the  treatment  of  infected  wounds,  are  the 
following :  ^ 

(a)  Hypochlorous  acid  and  its  sodium  and  other  salts 
(including  "eupad,"  "eusol"  and  so-called  Dakin's  solution). 

{h)  Chloramine-T,  the  abbreviated  name  for  sodium 
toluene  sulphonchloramide. 

{c)  Dichloramine-T,  the  abbreviated  name  for  toluene 
sulphondichloramine . 

In  most  respects,  the  action  of  these  various  chlorine 
compounds  is  essentially  similar,  though  each  possesses 
certain  properties  which  render  it  more  or  less  suitable  for 

1  Brit.  Med.  Journ.,  Jan.  29,  1916,  June  17,  1916;  Proc.  Roy.  Soc.  B,  8q, 
p.  232,  1916.     Biochem.  Journ.,  June,  IQ17. 

'  Brit.  Med.  Journ.,  April  29,  1916. 

^  Chlorine  water  has  been  used  to  some  extent,  but  it  is  doubtful  whether  its 
use  is  preferable  to  that  of  the  more  convenient  iodine  solution,  which  in  most 
respects  it  resembles. 


20  A   HANDBOOK   OF   ANTISEPTICS 

particular  purposes.     As  a  matter  of  convenience,  it  may 
be  desirable  to  give  a  short  resume  of  these  considerations. 

I.  Hypochloroiis  acid  and  hypochlorites  are  best  suited  to 
cleansing  septic  wounds  by  irrigation.  They  markedly 
assist  in  the  dissolution  of  necrosed  tissue.  They  are  unstable 
and  very  reactive,  and  must  be  frequently  renewed  to  all 
parts  of  a  wound,  this  being  best  achieved  by  the  method  of 
intermittent  instillation  (p.  13).  They  are  the  cheapest 
antiseptics  of  the  chlorine  group  and  are  much  cheaper  than 
other  effective  germicidal  substances.  Free  hypochlorous 
acid  is  more  irritating  than  the  sodium  salt.  The  latter  in 
0.5  per  cent  neutral  or  feebly  acid  (boric  acid)  solution  may 
be  used  in  large  quantities  under  appropriate  precautions 
for  a  considerable  time  without  causing  irritation.  The 
skin  is  more  susceptible  than  the  deeper  tissues  and  should 
be  protected  with  vaseline  or  some  similar  substance. 

II.  Chloramine-T  can  be  used  in  stronger  solution  (up  to 
two  per  cent)  than  the  hypochlorites.  It  is  more  stable 
and  exerts  more  prolonged  antiseptic  action  and  is  consider- 
ably more  effective  than  hypochlorite  when  acting  in  the 
presence  of  much  blood.  It  is  not  toxic  and  is  less  irritating 
than  the  hypochlorites  and  has  but  little  solvent  action  on 
necrosed  tissue.  It  is  well  suited  for  use  on  wounds  previously 
cleansed  with  hypochlorites  or  dichloramine-T,  and  in  suitably 
dilute  solutions  may  be  used  in  the  eye  and  on  other  sensitive 
parts.  It  may  be  applied  in  solution,  as  an  impregnation 
of  gauze,  or  in  a  sodium  stearate  cream. 

III.  Dichloramine-T  dissolved  in  oily  media  may  be 
sprayed  upon  wound-surfaces  or  poured  into  accessible 
parts  of  deep  wounds.  It  yields  moderate  amounts  of  anti- 
septic to  watery  media  such  as  secretions  from  wounds  or 
mucous  membranes.  It  is  suitable  for  cases  requiring  pro- 
longed antiseptic  treatment,  and  for  first  dressings  of  recent 
wounds  which  do  not  require  irrigation.  It  is  also  used  for 
nasal  antisepsis  (p.  102).     Dichloramine-T  in  oil  solution  has  a 


ANTISEPTICS   OF    THE   CHLORINE   GROUP  21 

great  advantage  over  the  other  chlorine  antiseptics  in  that 
it  may  be  used  in  high  concentration,  and  its  action  is  of  much 
longer  duration.  The  application  of  the  oil  is  extremely 
simple  and  it  ordinarily  need  not  be  renewed  more  than  once 
in  24  hours. 

Hypochlorous  Acid  and  its  Salts 

The  disinfecting  action  of  these  substances  has  been  known 
for  over  a  hundred  years  and  they  have  received  numerous 
hygienic  applications.  An  account  of  their  early  history 
and  uses  will  be  found  in  the  British  Medical  Journal,  Dec. 
4,  191 5.  In  the  early  part  of  the  present  war,  several 
surgeons  made  use  of  commercial  sodium  h}qDOchlorite,  "eau 
de  Javel,"  for  the  treatment  of  infected  wounds,  but  there 
were  many  accidents  owing  to  its  caustic  action,  which  was 
largely  due  to  the  presence  of  excessive  amounts  of  alkali 
in  the  solution.  Apart  from  this  objectionable  property, 
the  substance  appeared  to  possess  desirable  qualities  and  it 
was  for  this  reason  that  several  workers  sought  to  obtain 
hypochlorite  solutions  which  were  less  irritating  but  which 
retained  their  germicidal  properties  unchanged. 

These  various  solutions  are  all  prepared  from  bleaching 
powder  (chloride  of  lime)  which  is  the  most  readily  accessible 
solid  source  of  hypochlorous  acid  and  its  salts.  Bleaching 
powder  is  prepared  by  the  action  of  chlorine  upon  slaked 
lime  and  in  most  respects  behaves  like  a  mixture  of  calcium 
hypochlorite  and  calcium  chloride.  It  is  of  variable  com- 
position and  slowly  decomposes  on  keeping,  especially  when 
exposed  to  air  or  light  (p.  41).  In  making  some  of  the  anti- 
septic solutions,  the  calcium  hypochlorite  of  the  bleaching 
powder  is  converted  into  sodium  hypochlorite  by  the  action 
of  sodium  carbonate.  In  most  of  them  boric  acid  is  added 
to  counteract  the  objectionable  alkalinity  of  ordinary  hypo- 
chlorites, and  this  has  also  the  effect  of  liberating  a  certain 


22  A   HANDBOOK   OF   ANTISEPTICS 

amount  of  free  hypochlorous  acid,  leaving  the  solution 
neutral  or  faintly  acid.  Sodium  hypochlorite  may  also  be 
prepared  by  the  electrolysis  of  sodium  chloride  solution 
(p.  ii6)  and  by  the  action  of  chlorine  on  sodium  carbonate 
or  sodium  bicarbonate.  It  will  be  impossible  to  describe 
the  preparation  and  uses  of  all  the  various  hypochlorite 
solutions  that  have  been  employed  for  surgical  use  and  it 
would  appear  sufficient  to  give  an  account  of  the  two  that 
seem  to  be  most  widely  used,  namely ''  eusol "  and  the  so-called 
Dakin  solution.  All  hypochlorite  solutions  attack  metals 
and  hence  they  should  not  be  used  for  the  sterilization  of 
instruments. 

EuPAD  AND  EusoL.^  —  These  are  preparations  of  bleaching 
powder  and  boric  acid,  either  dry  (eupad)  or  in  solution 
(eusol).  The  former  is  prepared  by  intimately  mixing  equal 
weights  of  bleaching  powder  and  boric  acid,  both  in  fine 
powder.  It  has  been  employed  as  a  dusting  powder,  and  in 
strands  of  gauze  for  drainage  or  between  layers  of  moistened 
gauze  or  lint  as  a  dressing.  When  moistened,  eupad  liberates 
hypochlorous  acid  partly  in  gaseous  form  and  in  variable 
amount  and  this,  if  excessive,  is  liable  to  prove  highly  irri- 
tating, so  that  the  quantity  of  eupad  used  must  be  carefully 
controlled.  Eupad  forms  a  rather  thick,  white  coagulum 
with  wound  exudates  and  this  may  occasion  inconvenience. 
It  is  used  much  less  extensively  than  is  the  aqueous  eusol. 
An  almost  identical  mixture  was  recommended  by  Vincent 
some  years  ago  while  Lumiere  advocates  a  mixture  con- 
taining bleaching  powder  one  part  with  boric  acid  three 
parts. 

Eusol  is  prepared  in  either  of  two  ways : 

(i)  Twenty-five  grams  of  eupad  are  shaken  up  with  one 
liter  of  water,  allowed  to  stand  for  a  few  hours,  then  filtered 
through  cloth  or  filter  paper. 

1  Lorrain  Smith,  Drennan,  Rettie,  and  Campbell,  Brit.  Med.  Journ.,  July  24, 
1915. 


ANTISEPTICS   OF    THE   CHLORINE   GROUP  23 

(2)  To  I  liter  of  water  add  12.5  grams  bleaching  powder, 
shake  vigorously.  Then  add  12.5  grams  boric  acid  powder 
and  shake  again.  Allow  to  stand  for  some  hours,  preferably 
overnight,  then  filter  off,  and  the  clear  solution  is  ready  for 
use.  Eusol  prepared  in  this  way  from  good  quaUty  bleaching 
powder  contains  the  equivalent  of  about  0.27  per  cent  hypo- 
chlorous  acid.^  The  solution  gives  thick  precipitates  contain- 
ing calcium  with  blood  or  wound  exudates  and  is  strongly 
haemolytic.  It  is  frequently  spoken  of  as  a  solution  of 
hypochlorous  acid  but  actually  the  mixture  is  alkaline  to 
litmus  and  contains  a  balanced  mixture  of  calcium  hypo- 
chlorite and  borate  with  an  undetermined  amount  of  free 
hypochlorous  acid.  The  separate  estimation  of  the  latter 
is  a  difficult  problem.  A  large  number  of  experiments  on 
the  germicidal  action  of  eusol  will  be  found  in  Lorrain  Smith's 
paper,  together  with  suggestions  as  to  methods  of  use  in  the 
treatment  of  infected  wounds.  It  is  recommended  by  its 
authors  for  use  {a)  as  a  lotion,  diluted  if  necessary,  {h)  as  a 
fomentation,  (c)  as  a  wet  dressing  with  gauze  without  a 
waterproof  covering,  and  {d)  as  a  bath,  diluted  if  necessary. 

The  general  principles  concerning  the  use  of  chlorine  anti- 
septics as  germicides  apply  equally  to  eusol  and  the  other 
hypochlorites  (cp.  pp.  12,  20). 

Neutral  Sodium  Hypochlorite  Solution  ("Dakin's 
Solution"). — This  preparation  is  essentially  a  solution  of 
sodium  hypochlorite,  containing  0.45  to  0.5  per  cent  NaClO 
made  in  such  a  way  that  it  is,  and  remains,  substantially 
neutral.  Ordinarily  commercial  hypochlorite  is  very  variable 
in  composition  and  commonly  contains  much  free  alkali 
and  occasionally  free  chlorine.  Such  solutions  are  very 
irritating  and  should  not  be  used  for  surgical  purposes.  The 
original  formula  ^  for  making  the  neutral  solution  requires 

1  Through  an  error  in  calculation,  the  composition  was  first  given  as  0.54 
per  cent.  The  other  analytical  figures  given  in  the  original  paper  also  contain 
errors. 

»  Comptes  rendus,  161,  p.  150,  1915,  Brit,  Med.  Journ.,  Aug.  28,  1915. 


24  A   HANDBOOK   OF   ANTISEPTICS 

the  use  of  boric  acid  for  neutralization.  The  reason  for  this 
may  perhaps  be  briefly  referred  to.  It  is  well  known  that 
blood  and  some  other  body  fluids  and  also  certain  artificial 
salt  solutions  containing  mixtures  of  the  salts  of  polybasic 
acids  —  e.g.  phosphoric  or  carbonic  acid  —  are  able  to  retain 
their  essential  neutrality  even  after  the  addition  of  limited 
quantities  of  acid  or  alkali.  This  is  due  to  the  fact  that  the 
addition  of  acid  or  alkali  simply  changes  the  relative  pro- 
portion of  two  or  more  salts  of  the  polybasic  acid  present  in 
the  solution.  Such  solutions  are  often  referred  to  as  "  bal- 
anced "  and  the  salts  in  them  are  called  "buffer  salts."'  Uti- 
lizing the  same  principle  and  employing  the  feeble  polybasic 
boric  acid,  a  simple  balanced  hypochlorite  mixture  was 
prepared  which  maintains  essential  neutrality  under  all 
conditions.  It  should  be  understood  that  the  insignificant 
antiseptic  action  of  boric  acid  has  nothing  to  do  with  the  em- 
ployment of  this  acid  nor  is  the  boric  acid  employed  for  the 
purpose  of  liberating  free  hypochlorous  acid  as  in  Lumiere's 
or  Lorrain  Smith's  preparations. 

Preparation  of  Neutral  Sodium  Hypochlorite.  — 
One  hundred  and  forty  grams  of  dry  sodium  carbonate 
(Na2C03)  or  400  grams  of  the  crystallized  salt  (washing  soda) 
are  dissolved  in  10  liters  of  tap  water,  and  200  grams  of  bleach- 
ing powder  containing  24-28  per  cent  of  "available  chlorine  " 
are  added. ^  The  mixture  is  very  thoroughly  shaken,  both  to 
make  good  contact  and  to  render  the  precipitated  calcium 

1  Bleaching  powder  varies  considerably  in  its  available  chlorine  content, 
though  when  bought  in  bulk  the  fresh  product  is  fairly  constant  in  composition. 
It  is  advisable  to  determine  the  "  available  chlorine  "  in  each  large  batch  of  bleach- 
ing powder  purchased,  as  described  on  p.  41.  Bleaching  powder  with  less  than 
23  per  cent  of  available  chlorine  should  be  rejected.  Exceptional  samples  may 
contain  as  high  as  35  per  cent  available  chlorine  and  in  such  cases  it  is  well  to 
reduce  correspondingly  the  ingredients  taken  in  the  above  formula.  For  pur- 
poses of  rough  calculation,  one  may  assume  that  using  200  grams  of  bleaching 
powder  for  10  liters  of  solution,  the  resulting  product  will  contain  as  much 
sodium  hypochlorite  as  is  represented  by  the  available  chlorine  of  the  bleaching 
powder  divided  by  50.  Thus  25  per  cent  "  available  chlorine  "  bleaching  powder 
will  give  0.5  per  cent  sodium  hypochlorite  solution. 


ANTISEPTICS   OF   THE   CHLORINE   GROUP  25 

carbonate  granular  and  promote  its  settling.  It  is  then 
allowed  to  stand  quietly  and  after  half  an  hour  the  clear  liquid 
is  siphoned  off  from  the  precipitate  and  filtered  through  a 
cotton  plug  or  paper.  Forty  grams  of  boric  acid  are  added  to 
the  clear  filtrate  and  the  resulting  solution  is  ready  for  use. 
The  boric  acid  must  not  be  added  before  filtering  but  only 
afterwards.  The  exact  strength  should  be  determined  from 
time  to  time,  as  directed  on  p.  41.  It  is  important  that  the 
solution  should  not  be  stronger  than  0.5  per  cent  sodium 
hypochlorite  or  irritation  of  the  skin  may  be  frequent.  On 
the  other  hand,  it  should  not  be  less  than  0.4  per  cent  or  its 
germicidal  action  is  materially  diminished.  The  solution 
should  also  be  tested  for  neutrality  by  adding  a  Httle  of  it 
to  a  trace  of  solid  phenolphthalein  suspended  in  water.  No 
red  color  indicating  free  alkali  should  develop  or  else  more 
boric  acid  must  be  added ;  this  is,  however,  rarely  necessary 
with  the  above  proportions.  The  solution  should  not  be 
kept  longer  than  one  week.^ 

Daufresne  has  shown  that  it  is  possible  to  prepare  a  satis- 
factory solution  of  sodium  hypochlorite  without  employing 
boric  acid  for  neutralization  if  sodium  bicarbonate  be  used 
in  conjunction  with  sodium  carbonate  for  decomposing  the 
bleaching  powder.  The  relative  proportions  of  sodium 
carbonate  and  bicarbonate  required   to  furnish  a  neutral 

1  A  stronger  solution  may  be  prepared  by  decomposing  bleaching  powder 
with  dry  sodium  carbonate  in  the  proportion  of  150  gms.  to  105  gms,  dissolved 
in  I  liter  of  water.  The  mixture  is  filtered  and  a  measured  portion  of  it  (20  cc.) 
rapidly  titrated  with  a  boric  acid  solution  of  known  strength  (31  gms.  per  liter, 
i  normal)  using  phenolphthalein  suspended  in  water  as  indicator  (the  usual  alco- 
holic solution  of  phenolphthalein  will  not  serve,  because  the  alcohol  is  at  once  at- 
tacked) in  order  to  determine  the  amount  of  boric  acid  to  be  added  to  the  rest 
of  the  filtrate.  (Each  cubic  centimeter  of  N/2  boric  acid  calls  for  3  gms.  boric 
acid  to  be  added.)  An  excess  of  boric  acid  should  be  avoided  as  it  favors  the 
liberation  of  hypochlorous  acid  and  renders  the  solution  less  stable.  It  is  best 
to  adrl  slightly  less  than  the  calculated  amount.  The  concentrated  solution 
ihus  prepared  contains  about  4  per  cent  of  sodium  hypochlorite  and  should  be 
mixed  with  7  parts  of  water  before  use.  It  can  be  kept  for  a  month  without 
serious  decomposition. 


26  A    HANDBOOK  OF   ANTISEPTICS 

solution  depends  upon  the  varying  composition  of  the  bleach- 
ing powder  used  and  cannot  simply  be  deduced  from  its 
"  available  chlorine  "  content,  as  is  frequently  stated.  The 
proportion  of  free  lime  in  the  bleaching  powder  is  obviously 
as  important  as  its  chlorine  strength.  With  some  brands 
of  bleaching  powder  retailed  in  the  United  States,  the  fol- 
lowing proportions  have  proved  useful : 

Two  hundred  grams  of  bleaching  powder  (24-28  per  cent 
available  chlorine)  ^  is  shaken  well  with  five  liters  of  water 
and  allowed  to  stand  for  an  hour  or  two.  In  a  separate 
vessel  dry  sodium  carbonate  (94  grams)  and  sodium  bicar- 
bonate (86  grams)  are  mixed  with  five  liters  of  cold  water, 
and  when  dissolved,  the  solution  is  added  to  the  bleaching 
powder  suspension  and  the  mixture  well  shaken.  The  pre- 
cipitate of  calcium  carbonate  is  allowed  to  settle  and  the 
clear  supernatant  solution  is  syphoned  off  and  filtered.  The 
solution  should  contain  close  to  0.5  per  cent  sodium  hypo- 
chlorite and  this  should  be  checked  by  analysis  (p.  41).  If 
too  strong  it  should  be  diluted  with  water  to  0.5  per  cent 
strength. 

It  is  most  important  to  test  the  solution  for  free  alkali  by 
adding  a  trace  of  solid  phenolphthalein  to  a  little  of  it.  In 
case  a  red  color  develops  indicating  free  alkali,  the  solution 
may  still  be  used  if  it  is  previously  neutralized  either  by 
passing  carbon  dioxide  through  the  solution  or  by  adding  a 
little  boric  acid,  until  the  alkaline  reaction  is  abolished.  But 
in  making  .further  quantities  of  the  solution,  using  the  same 
sample  of  bleaching  powder,  alkalinity  may  be  avoided  by 
reducing  the  quantity  of  sodium  carbonate  and  correspond- 
ingly increasing  the  bicarbonate. 

Sodium  hypochlorite,  whether  prepared  according  to  the 
preceding  formulae  or  according  to  other  methods  that  will 
occur  to  the  chemist,  e.g.  from  salt  by  electrolysis  (p.  116) 
or  from  liquefied  chlorine  gas,  when  used  in  neutral  solution 

1  Or  an  equivalent  amount  of  stronger  bleaching  powder. 


ANTISEPTICS   OF    THE   CHLORINE   GROUP  27 

at  0.5  per  cent  concentration  is  found  to  be  a  valuable  anti- 
septic for  the  treatment  of  infected  wounds.  Its  action  is 
extremely  rapid  and  then  ceases  as  soon  as  all  the  hypo- 
chlorite is  decomposed,  hence  the  methods  for  using  the  solu- 
tion efficiently  must  provide  for  its  frequent  renewal.  A 
short  account  of  the  technique  advocated  by  Carrel  and 
Dehelly  will  be  found  on  p.  13.  For  further  details,  reference 
may  be  made  to  their  book  and  to  the  papers  noted  below.^ 

The  hypochlorite  solutions  possess  the  valuable  property 
of  assisting  in  the  rapid  dissolution  of  necrotic  tissue,  doubt- 
less owing  to  their  ability  to  react  with  proteins  with  the 
formation  of  soluble  products.  They  possess  a  slight  but 
definite  haemostatic  action  but  are  actively  hsemolytic  and 
should  not  be  injected  intravenously.  The  hypochlorites 
are  extremely  reactive  substances  chemically,  and  should 
neither  be  heated  above  37°  C.  or  used  with  other  antiseptics 
nor  with  alcohol  nor  ether. 

It  is  rather  difficult  to  give  useful  figures  for  the  germicidal 
effects  of  sodium  hypochlorite  since  so  much  depends  on  the 
capacity  of  the  medium  to  decompose  the  hypochlorite 
before  it  can  complete  disinfection.  Most  pyogenic  organ- 
isms suspended  in  water  are  killed  at  a  concentration  of  less 
than  1 :  100,000,  while  in  serum  about  i :  1500  is  necessary. 
Blood  decomposes  the  hypochlorites  rapidly,  so  that  i :  300  or 
more  may  be  necessary  before  sterilization  is  complete.  The 
action  of  sodium  hypochlorite  and  eusol  on  a  mixture  of  pyo- 
genic and  other  organisms  in  a  blood  serum  muscle  extract 
mixture  is  recorded  on  p.  85.  The  lethal  concentration  under 
the  stated  conditions  is  probably  a  little  less  than  i :  1000. 

^  Le  traitement  des  plaies  infectes.  A.  Carrel  &  G.  Dehelly.  Masson  at 
Cie.,  Paris,  1917. 

Carrel,  Dakin,  Daufresne,  Dehelly,  and  Dumas.     Presse  Medicale,  Oct.  11, 

1915- 

TufBer,  Bull,  de  I'Acad.  de  Med.,  74,  No.  38,  1915. 

Depage,  A.,  Bull,  et  Mem.  Soc.  de  chir.  de  Paris,  42,  p.  1987,  1916. 

Lyle,  H.  H.  M.,  Journ.  Am.  Med.  Assoc,  Jan.  13,  1917. 


28  A   HANDBOOK   OF   ANTISEPTICS 

The  "Extraordinary  rapidity  of  its  action  in  concentrations 
even  lower  than  those  employed  for  surgical  purposes  is  well 
illustrated. 

Chloramine-T 

Chloramine-T  is  the  abbreviated  name  for  sodium  toluene- 
sulphonchloramide.^  It  is  a  crystalline,  odorless  substance 
containing  12.6  per  cent  of  chlorine.  It  is  readily  soluble 
in  water  and  the  solutions,  which  have  a  bitter  taste,  are 
stable,  neither  moderate  exposure  to  heat  nor  light  caus- 
ing appreciable  decomposition.  In  equimolecular  solutions 
its  germicidal  activity  is  about  four  times  that  of  sodium 
hypochlorite.  This  may,  perhaps,  be  explained  by  the  fact 
that  the  chlorine  is  already  linked  to  nitrogen  and  is  less 
rapidly  appropriated  through  reactions  with  proteins  and 
other  substances  in  the  wound  secretions.  The  relatively 
slight  solvent  action  of  chloramine-T  on  necrosed  tissue 
supports  this  view.  Its  antiseptic  efhciency  is  prolonged 
by  this  reduction  in  reactivity.  Its  germicidal  action  is 
rapidly  exerted  and  in  most  respects  it  resembles  the  hypo- 
chlorites closely,  though  decidedly  less  irritating  than  the 
latter.  An  idea  of  its  potency  may  be  gathered  from  the 
accompanying  tables,  although  in  some  respects  a  better 
indication  is  given  by  the  results  recorded  in  a  later  chapter 
(p.  86). 

In  another  series  of  experiments  note  was  taken  of  the 
speed  of  disinfection.  Horse  blood  serum  (2  cc.)  or  0.7  per 
cent  Witte's  peptone  (2  cc.)  was  inoculated  with  staphy- 
lococcus aureus  and  subsequently  treated  with  weak  chlora- 
mine-T solutions  (i  cc).  The  results  show  clearly  that  the 
rate  of  disinfection  is  very  rapid,  the  maximum  effect  being 
observed  in  a  few  minutes.  In  those  cases  where  disinfection 
was  incomplete  and  no  active  antiseptic  persisted  in  the 
mixture,  subsequent  growth  took  place  (p.  30). 

1  Dakin,  Cohen,  and  Kenyon,  Brit.  Med.  Journ.,  Jan.  29,  1916. 


ANTISEPTICS   OF    THE   CHLORINE   GROUP 


29 


Table  showing  the  Germicidal  Action  of  Chloramine-T  on  Several 

Common  Organisms 

Two  drops  of  a  fresh  culture  of  the  organisms  were  suspended  in  s  cc.  of 
fluid  either  water  or  50  per  cent  horse  serum,  and  the  antiseptic  was  allowed  to 
act  two  hours  at  room  temperature.  The  mixtures  were  then  subcultured.  In 
comparison,  a  few  figures  for  sodium  hypochlorite  and  phenol  are  added. 


Staphylococci  in  water  . 

Staphylococci  in  serum 

B.  pyocyaneus  in  water 

B.  pyocyaneus  in  serum 

Streptococci  in  water     . 
Streptococci  in  serum    . 

B.  capsulatus  in  water  . 
B.  capsulatus  in  serum 


Chloramine-T 


500,000  — 
1,000,000  + 
1,500  - 
2,500  + 
200,000  — 
400,000  + 
1,250  - 
2,000  + 
1,000,000  — 
2,500  - 
5,000  + 
i,ooo,oco  — 

2,500  - 
5,000  + 


Sodium 

Phenol 

Hypochlorite 

X  :  500,000  — 

1 :  250  - 

1 :  1,000,000  + 

1 :  500  + 

1 :  1,500  - 

1:50  - 

1 :  2,000  H- 

1 :  100  + 

1 :  100,000  — 

1 :  200  — 

1 :  1,000,000  + 

I  :  400  + 

1 :  2,500  — 

i:  25  - 

1 :  5,000  + 

i:  50  + 

Complete  sterilization  is  indicated  by  -,  while  +  indicates  th^t  organisms 
survived. 

Chloramine-T  may  be  used  for  wound  treatment  in  solu- 
tion, in  the  dry  state  as  an  impregnation  of  gauze,  or  m  a 
cream-like  paste,  all  these  methods  having  proved  efficient 

and  useful.  .   . 

In  Solution.  —  At  first,  solutions  contammg  as  much  as 
4  per  cent  of  chloramine-T  were  used  in  the  treatment  ot 
wounds.  Although  there  were  no  cases  reported  to  show 
that  these  were  unduly  irritating,  subsequent  experience 
has  shown  that  there  is  no  occasion  for  exceeding  a  concen- 
tration of  2  per  cent.  For,  as  chloramine-T  has,  weight  for 
weight,  as  great  a  germicidal  power  as  sodium  hypochlorite, 
a  2  per  cent  solution  is  considerably  more  potent  than  the 


30 


A   HANDBOOK   OF   ANTISEPTICS 


Medium 

Concentration  of 

Chloramine-T  in 

the  Mixture 

Time  of 
Action 

Bacterial 

Count 

(i  Drop  =  3V  cc.) 

Blood  Serum      .... 

1 : 1000 

0 

1751 

5  mm. 

0 

15  mm. 

0 

Blood  Serum      .... 

1 :  2000 

45 
0 

0 

1831 

5  min. 

9^ 

15  mm. 

15 

Blood  Serum      .... 

1 :  3000 

45  min. 
0 

49 
1509 

5  mm. 

96  1 

15  mm. 

82 

Peptone  0.7  per  cent  .     . 

1 :  5000 

45  mm. 
0 

2X1 
9360 

5  mm. 

0 

15  mm. 

0 

Peptone  0.7  per  cent  .     . 

1 :  6000 

45  mm. 
0 

0 
1323 

5  mm. 

13^ 

15  mm. 

12 

45  mm. 

14 

solution  of  sodium  hypochlorite  usually  employed  (0.5  per 
cent).  The  2  per  cent  solution  may  be  used  for  the  treat- 
ment of  septic  wounds,  using  the  same  methods  as  employed 
for  the  hypochlorites. 

It  must  be  borne  in  mind  that  in  severe  septic  conditions 
much  of  the  chloramine-T  is  promptly  decomposed  by  the 
secretions.  This  is  true  of  all  antiseptics  of  the  chlorine 
group  and  is  even  more  marked  in  the  case  of  hypochlorites 
than  with  chloramine-T.  While  this  circumstance  undoubt- 
edly exerts  a  favorable  influence  through  the  destruction  of 
substances  of  a  toxic  nature,  it  reduces  the  germicidal 
activity  of  .the  solution.  It  follows  also  that  where  sepsis 
is  less  marked,  much  weaker  solutions  may  be  employed. 

1  All  antiseptic  decomposed.    No  active  chlorine  present. 


ANTISEPTICS   OF    THE   CHLORINE   GROUP  31 

In  the  eye,  for  example,  a  solution  of  one  part  of  chloramine-T 
in  a  thousand  parts  of  normal  saline  solution  will  exert  a 
satisfactory  germicidal  action,  while  i :  500  may  prove 
rather  irritating  to  the  inflamed  conjunctiva.  Here,  because 
of  the  constant  irrigation  by  tears,  there  is  chance  for  only 
a  moderate  accumulation  of  septic  products  likely  to  reduce 
the  strength  of  the  application.  In  cystitis,  the  tolerance 
often  appears  to  be  less  than  in  the  eye,  and  it  is  advisable 
to  start  treatment  with  a  weak  solution,  increasing  the 
strength  according  to  the  degree  of  tolerance  manifested. 
In  chronic  urethral  infections,  i :  500  can  be  used  for 
the  initial  injections  and  the  concentrations  subsequently 
increased.  Similar  considerations  apply  to  the  irrigation 
of  the  pleural  cavity  in  empyema.  The  use  of  chloramine-T 
for  the  disinfection  of  meningococcus  carriers  is  referred  to 

on  p.  100. 

From  the  foregoing  statements  it  will  be  evident  that  the 
choice  of  strength  to  be  used  must  be  left  to  the  judgment 
of  the  surgeon.  In  practice  it  is  advisable  to  keep  a  2  per  cent 
solution  in  stock  and  to  dilute  this,  if  necessary,  either  with 
water  or,  in  case  of  considerable  dilution,  with  normal  saUne 
solution.  A  2  per  cent  solution  is  slightly  hypotonic  and 
when  an  approximately  isotonic  medium  is  desired,  normal 
saline  solution  should  be  used  as  a  diluent.  Chloramine-T, 
like  hypochlorites,  has  a  corrosive  action  on  most  metals 
and  should  not  be  used  for  the  sterilization  of  instruments. 
In  Impregnated  Gauze.  —  Chloramine-T  is  well  adapted 
to  this  use,  for  which  very  few  substances  of  high  antiseptic 
value  have  proved  successful.  It  is  possible,  for  example, 
to  incorporate  as  much  as  25  per  cent  of  the  weight  of  the 
gauze.  This  is  a  much  larger  amount  than  is  advisable, 
5  per  cent  being  adequate.  Obviously  the  gauze  should  not 
be  moistened  before  use  lest  the  antiseptic  be  washed  out 
because  of  its  ready  solubility.  It  can  be  used  dry  for 
lightly  packing  and   subsequently  moistened  if   necessary 


32  A   HANDBOOK   OF   ANTISEPTICS 

when  in  position.  Impregnated  gauze  finds  application  in 
wounds  of  recent  origin  in  which  the  chief  object  is  to  pre- 
vent progress  of  infection.  It  is  particularly  adapted  to 
use  in  cases  of  industrial  accident  where  treatment  can  be 
promptly  instituted.  Where  frequent  renewals  of  the  anti- 
septic or  irrigation  are  called  for,  it  is  superfluous. 

In  Soap  Paste.  —  None  of  the  chlorine  .  group  of  anti- 
septics can  be  used  in  ointments  containing  fats  or  oils  as 
these  rapidly  withdraw  the  active  chlorine  with  the  pro- 
duction of  inert  compounds.  It  is  possible,  however,  with 
the  exceptionally  stable  chloramine-T  to  obtain  a  prepara- 
tion which  can  be  used  as  an  acceptable  substitute  for  oint- 
ments. A  preparation  of  this  sort  introduced  by  Daufresne,^ 
which  has  been  extensively  used,  contains  0.7  per  cent  to  i  per 
cent  of  chloramine-T  dissolved  in  water  containing  5-10  per 
cent  of  sodium  stearate.  It  is  important  that  the  mixture 
should  not  contain  any  substance  which  can  unite  with  chlo- 
rine to  form  an  inert  compound.  For  this  reason  the  stearate 
used  must  be  free  from  any  fatty  acid  of  an  unsaturated  series. 
The  paste  is  not  oleagenous.  It  has  a  creamy  consistency  and 
can  be  spread  readily.  As  the  antiseptic  is  dissolved  in  the 
water  constituting  the  chief  bulk  of  the  paste,  it  has  ready 
access  to  the  parts  treated. 

An  investigation  of  the  effect  of  this  chloramine-T  paste 
in  sterilizing  moderately  infected  wounds  and  maintaining 
asepsis  in  wounds  previously  sterilized  by  other  means,  has 
been  published  by  Carrel  and  Hartmann.^  Its  use  does  not 
delay  the  rate  of  cicatrization. 

Preparation.  —  Chlor8.mine-T  was  first  prepared  by  Chat- 
taway  ^  by  the  action  of  sodium  hydroxide  upon  toluene- 
sulphondichloramine  (dichloramine-T,  vide  infra)  .^      A  more 

1  Journ.  Exper.  Med.,  26,  p.  91,  1917.  ^  Ibid.,  p.  95,  1917. 

3  Trans.  Chem.  Soc,  87,  p.  153,  1905- 

4  Chloramine-T  is  manufactured  by  Messrs.  Boot,  Island  Street,  Nottingham, 
England,  and  several  other  firms.  It  is  also  marketed  by  the  Abbott  Laboratories, 
Cliicago,  under  the  name  of  Chlorazene. 


ANTISEPTICS   OF    THE    CHLORINE   GROUP  33 

economical  method  of  preparation  consists  in  dissolving 
toluene-p-sulphonamide  (i  mol.)  in  5  per  cent  cold  alkaline 
solution  of  sodium  hypochlorite  (1.2  mol.),  warming  gently 
if  necessary,  filtering,  and  adding  1^  vols,  of  saturated  salt 
solution.  The  chloramine-T  crystallizes  out  of  solution  as 
a  white  glistening  meal  of  crystals  and  is  filtered  off,  washed 
with  salt  solution,  and  dried  in  the  air.  The  product  con- 
tains three  molecules  of  water  of  crystallization.  If  it  is 
desired  to  free  the  substance  from  adherent  salt  left  from  the 
process  of  preparation,  it  may  be  obtained  pure  from  a  hot 
concentrated  solution,  from  which  on  slow  cooling  it  will 
separate  in  large  crystals.  The  purity  of  a  given  sample 
may  be  determined  by  titration  with  decinormal  thiosulphate 
solution,  as  described  on  p.  42. 

The  reaction  which  takes  place  in  the  above  preparation 
may  be  represented  as  follows : 

CH3  CH3 


+  NaClO  =1  +  H2O 


SO2NH2  SOoNaNCl 

Toluene-p-sulphonamide  Chloramine-T 

DiCHLORAMINE-T 

Dichloramine-T  is  the  abbreviated  name  for  toluene-p- 
sulphondichloramine.  It  is  a  yellowish  white  crystalline 
substance  possessing  a  sweetish,  rather  pungent  chlorous 
odor.  It  is  stable  in  the  solid  state  especially  when  kept  in 
the  dark.  Water  dissolves  only  traces  of  it,  though  it  is 
readily  soluble  in  most  organic  solvents  except  paraffin  or 
petroleum.  It  has  an  intense  germicidal  action  (pp.  86,  93) 
corresponding  to  its  high  content  of  active  chlorine,  but  it 
is  difficult  to  find  perfectly  satisfactory  solvents  for  it  which 
will  yield  stable  solutions.     Up   to   the  present,   the  best 


34  A  HANDBOOK  OF  ANTISEPTICS 

medium  that  we  have  been  able  to  find  is  an  oil  obtained  by 
the  chlorination  of  paraffin  wax,  to  which  the  name  of 
"  chlorcosane "  has  been  assigned.  Its  preparation  and 
properties  will  be  described  later  (p.  37).  Other  solvents  that 
have  been  used  are  mixtures  of  eucalyptol  and  paraffin  oil 
both  previously  treated  to  reduce  their  avidity  for  chlorine 
as  described  on  p.  39,  and  also  a  heavy  oil  (sp.  gr.  1.2)  ob- 
tained by  prolonged  chlorination  of  eucalyptol  which  was 
introduced  by  Lewis  and  Kraus.  On  the  whole,  "chlor- 
cosane"  appears  decidedly  preferable  to  the  other  solvents. 

Dichloramine-T  was  originally  used  in  oil  solution  for 
nasopharyngeal  disinfection  (p.  102),  but  more  recently  it  has 
found  a  wider  application  in  the  treatment  of  infected  wounds. 
The  results  obtained  in  the  treatment  of  industrial  injuries  by 
W.  E.  Lee  ^  and  his  colleagues  in  Philadelphia  and  by  J.  E. 
Sweet  ^  in  war  wounds,  have  been  extremely  satisfactory. 

It  will  be  well,  perhaps,  to  refer  first  of  all  to  the  way  in 
which  the  antiseptic  action  of  dichloramine-T  in  oil  solution 
is  exerted.  It  is  well  recognized  that  antiseptics  incorpo- 
rated with  or  dissolved  in  oily  substances  usually  possess 
little  if  any  antiseptic  activity  because  intimate  contact  with 
the  infected  matter  is  hindered  by  the  oil.  When,  however, 
such  oil  solutions  of  dichloramine-T  as  will  be  described  are 
brought  in  contact  with  aqueous  media,  the  partition  coeffi- 
cient between  the  oil  and  the  water  is  such  that  a  certain 
amount  of  dichloramine-T  passes  into  the  water  and  there 
exerts  its  germicidal  action.  The  amount  of  dichloramine-T 
thus  passing  from  the  oil  is  enhanced  by  the  presence  in  the 
aqueous  medium  of  substances  capable  of  taking  up  chlorine. 
So  that  the  oil  solution  serves  as  a  store  of  the  antiseptic 
which  is  drawn  upon  to  maintain  the  germicidal  activity  of 
the  aqueous  medium  with  which  it  is  in  contact.  Thus  the 
amount  of  active  antiseptic  leaving  the  oil  solution  is,  to  a 

1  Journ.  Amer.  Med.  Assoc,  July  7,  1917. 

2  Brit.  Med.  Journ.,  Aug.  25,  191 7. 


ANTISEPTICS  OF   THE  CHLORINE  GROUP  35 

considerable  extent,  dependent  upon  the  rate  at  which  it  is 
used  up  in  the  aqueous  medium. 

As  illustrating  the  influence  of  varying  conditions  on  the 
passage  of  the  active  chlorine  from  the  oil  to  an  aqueous 
medium,  the  following  experiments  may  be  cited.  A  6.5 
per  cent  solution  of  dichloramine-T,  prepared  as  described 
later,  was  mixed  {a)  with  an  equal  volume  of  saline,  {h)  with 
muscle  extract,  (c)  with  blood  serum.  The  oil  was  then 
separated  completely  after  3  hours.  The  active  chlorine 
stated  in  terms  of  dichloramine-T  in  the  saline  solution  was 
1 :  6000,  in  the  filtered  muscle  extract  i :  300,  and  in  serum 
which  was  mostly  coagulated  i  :  in.  It  is  thus  seen  that 
the  dichloramine-T  dissolved  in  the  oil  is  in  a  readily  avail- 
able form  and  direct  bacteriological  tests  following  its  action 
on  bacterial  suspensions  in  blood  and  muscle  extract  (p.  86) 
on  the  organisms  of  the  nasopharynx  (p.  102)  and  on  war 
wounds  have  clearly  show^n  its  germicidal  action  to  be  great. 

Dichloramine-T  is  best  employed  for  surgical  purposes  in 
a  5-8  per  cent  solution  in  chlorcosane  but  it  may  also  be  used 
dissolved  in  eucalyptol  and  parafiin.  The  solution,  however 
prepared,  must  be  kept  in  amber  glass  bottles,  since  direct 
sunlight  causes  its  rapid  decomposition.  Blue  glass  affords 
no  protection.  The. solution  is  often  most  conveniently  ap- 
plied by  means  of  an  oil  spray,  an  ordinary  hard  rubber  or 
all  glass  atomizer  being  best,  as  some  metals  are  slowly  at- 
tacked. If  the  chlorcosane  solution  should  prove  too  viscous 
for  convenient  spraying,  about  a  tenth  volume  of  carbon 
tetrachloride  may  be  added.  This  addition  should  only  be 
made  to  the  oil  used  in  a  spray.  The  undiluted  chlorcosane 
solution  may  be  poured  into  wound  cavities,  and  can  easily 
be  introduced  into  sinuses  by  means  of  a  cotton  swab  dipped 
in  the  solution.  The  amount  of  the  solution  needed  for  each 
treatment  is  extremely  small,  i  to  2  cc.  being  sufficient  for 
most  moderate-sized  wounds,  and  it  need  not  be  renewed 
more  often  than  once  in  24  hours.     A  minimum  of  dressings 


36  A  HANDBOOK  OF  ANTISEPTICS 

is  required  and  they  do  not  stick  to  the  granulation  tissue. 
Dichloramine-T,  hke  most  other  antiseptics  of  the  chlorine 
group,  is  an  active  lymphagogue  when  placed  on  fresh  wounds. 
As  granulation  tissue  develops,  the  lymph  discharge  decreases 
and  the  wound  becomes  comparatively  dry.  It  also  pos- 
sesses the  property  of  aiding  in  the  removal  of  necrotic  tissue. 
Wounds  treated  with  the  oil  fill  rapidly  with  granulation 
tissue  of  healthy  color  which  shows  no  tendency  to  exuberant 
growth  nor  to  become  sodden.  The  early  reports  as  to  the 
results  of  the  use  of  dichloramine-T  in  oil  solution  for  wound 
treatment  are  decidedly  encouraging  and  the  method  appears 
to  us  to  be  of  genuine  value  and  deserving  of  extended  use. 

Dichloramine-T  in  oil  solution  has  been  tried  extensively 
in  the  early  treatment  of  injuries,  not  only  of  the  soft  parts 
but  of  tendons,  bones,  and  joints.  At  the  primary  dressing 
of  these  wounds,  after  the  excision  of  dead  tissue  and  obvious 
foci  of  infection,  the  wound  is  liberally  flooded  with  the  oil 
and  then  closed  without  drainage.  In  Lee's  experience 
primary  union  follows  in  at  least  75  per  cent  of  these  sutured 
wounds  if  treated  within  three  hours  of  their  infliction.  If 
signs  of  infection  should  appear,  one  or  more  stitches  are  re- 
moved and  oil  is  introduced  by  means  of  a  grooved  director 
to  the  focus  of  infection  once  in  24  hours.  With  wounds 
treated  after  a  longer  interval  the  question  of  their  closure 
becomes  a  matter  of  surgical  judgment.  Dichloramine-T 
in  oil  has  also  been  found  decidedly  useful  in  the  treatment 
of  boils  and  carbuncles  with  minimal  incision,  in  osteomye- 
litis, non- tuberculous  empyema  and  in  the  control  of  post- 
operative wound  infection.  More  recently  it  has  been  used 
by  Lee  for  the  treatment  of  burns,  and  in  these  cases  it  is 
ad\dsable  to  cover  the  tissues  with  one  layer  of  a  coarse- 
meshed  gauze  or  mosquito  netting  previously  soaked  in 
melted  parafhn  wax.  In  this  way  the  exudate  easily  comes 
through  the  open  mesh  and  the  dressings  do  not  stick.  It 
is  an  advantage  if  such  wounds  can  be  exposed  to  the  air. 


ANTISEPTICS  OF  THE  CHLORINE  GROUP  37 

The  absence  of  suppuration  and  freedom  of  drainage  in  these 
cases  is  significant. 

Preparation  of  Dichloramine-T .  —  The  following  details  are 
based  on  the  method  employed  by  Chattaway :  Bleaching 
powder  (350  to  400  gms.)  of  good  quaUty  (25  per  cent  or 
more  "available  chlorine  ")  is  shaken  with  two  Hters  of  water 
in  a  shaker  for  an  hour  and  then  the  mixture  allowed  to  settle. 
The  supernatant  fluid  is  siphoned  off  and  the  remainder 
filtered.  Powdered  toluene-sulphonamide  (75  gms.)  is  then 
added  to  the  whole  of  the  hypochlorite  solution  and  shaken 
till  dissolved.  The  solution  is  filtered  if  necessary,  placed 
in  a  large  separating  funnel,  and  acidified  with  acetic  acid 
(100  cc.)  added  in  portions.  About  100  cc.  of  chloroform 
are  then  added  to  extract  the  dichlor amine  precipitated  by 
the  acid,  and  the  whole  well  shaken.  The  chloroform  layer 
is  tapped  off,  dried  over  calcium  chloride,  filtered,  and  allowed 
to  evaporate.  The  residue  is  powdered  and  dried  in  vacuo. 
It  is  sufficiently  pure  for  most  purposes  without  recrystalUza- 
tion.  The  yield  is  practically  theoretical.  The  product 
may  be  tested  by  titration  with  thiosulphate  solution  (p.  42). 
Its  preparation  may  be  represented  as  follows : 

CH3  CH3 


SO2NH2  SO2NCI2 

p-Toluenesulphonamide  Dichloramine-T 

Preparation  of  '  Solvents  for  Dichloramine-T.  — 
Chlorcosane.  —  This  is  at  present  the  most  satisfactory  sol- 
vent for  dichloramine-T  and  is  prepared  as  follows  :  Paraffin 
wax,  preferably  melting  at  50°  C,  or  higher,  is  placed  in 
round  bottomed  flasks  and  heated  to  about  120°.  Two 
flasks  connected  in  series,  each  containing  a  half  kilo  of  the 
wax,  may  be  conveniently  used.     A  rapid  current  of  chlorine 


38  A  HANDBOOK  OF  ANTISEPTICS 

from  a  cylinder  of  the  liquefied  gas  is  then  passed  through  the 
molten  wax  in  the  flasks,  each  of  which  is  provided  with  a 
thermometer  and  the  necessary  glass  tubes.  The  tempera- 
ture should  be  controlled  within  the  limits  of  125-140°.  The 
first  flask  in  which  the  reaction  is  most  vigorous  will  require 
but  little  heating.  Chlorination  is  continued  until  the  con- 
tents of  the  flasks  have  increased  in  weight  45-55  per  cent  of 
the  weight  of  wax  taken.  It  will  be  found  convenient  to 
complete  the  chlorination  of  the  first  flask  and  then  remove 
it,  and  transfer  the  second  to  its  place,  putting  a  fresh  flask 
of  paraffin  wax  after  it.  In  order  to  avoid  undue  discolora- 
tion of  the  product,  a  minimum  amount  of  rubber  tubing 
should  be  used  for  the  connections.  Wide  glass  tubing  should 
be  used  for  passing  the  gases,  and  the  ends  of  the  delivery 
tubes  are  preferably  blown  into  small  bulbs  provided  with  a 
number  of  fine  orifices  to  promote  good  contact  between  the 
gas  and  oil.  Hydrochloric  acid  is  of  course  evolved  freely 
during  the  reaction.  After  the  requisite  amount  of  chlorine 
has  been  absorbed,  the  oil  while  still  warm  is  shaken  vigor- 
ously with  five  per  cent  of  its  weight  of  dry  sodium  carbonate 
and  then  filtered  through  a  dry  fluted  paper.  The  clear  oil, 
which  has  a  light  yellow  or  sherry  color  and  is  slightly  heavier 
than  water,  is  then  ready  for  use.  It  possesses  a  viscosity 
intermediate  between  that  of  olive  oil  and  castor  oil,  has 
almost  no  odor,  and  is  perfectly  bland  when  sprayed  up  the 
nose  or  placed  on  skin  or  wounds.  It  will  be  noted  that  the 
materials  necessary  for  making  the  solvent  are  all  easily  avail- 
able at  very  cheap  rates.  As  was  to  be  expected,  the  prod- 
uct is  not  a  single  individual  compound,  but  a  mixture  of 
isomeric  and  homologous  chlorine  derivatives.  It  is  there- 
fore impossible  to  give  a  systematic  name  to  the  product, 
and  as  the  descriptive  name  ''chlorinated  paraffin  wax  oil'' 
seems  unnecessarily  clumsy,  we  have  chosen  the  name  "chlor- 
cosane"  since  the  systematic  names  of  most  of  the  hydro- 
carbons in  paraffin  wax  end  with  the  suffix  "  cosane."     Chlor- 


ANTISEPTICS  OF   THE  CHLORINE  GROUP  39 

cosane  itself  contains  all  its  cfilorine  united  to  carbon  and 
has  no  appreciable  antiseptic  action. 

Chlorinated  Eucalyptol.  —  Eucalyptol  (U.  S.  P.  or  Brit. 
Pharm.)  and  not  eucalyptus  oil,  must  be  used.  Five  hun- 
dred cc.  are  treated  with  15  gms.  potassium  or  sodium  chlo- 
rate and  50  cc.  concentrated  hydrochloric  acid  for  12  hours 
or  longer.  It  is  then  well  washed  in  a  separating  funnel,  first 
with  water  and  then  with  a  solution  of  sodium  carbonate,  to 
remove  all  traces  of  hydrochloric  acid.  After  tapping  off 
the  aqueous  layer,  15  gms.  dry  sodium  carbonate  are  added 
to  the  oil  and  the  whole  allowed  to  stand  for  24  hours.  It  is 
then  filtered,  further  dried  mth  a  little  solid  calcium  chloride, 
which  must  be  allowed  to  act  for  a  considerable  time,  and  is 
then  ready  for  use. 

Chlorinated  Paraffin  Oil.  —  This  may  be  used  for  diluting 
solutions  of  dichloramine-T  in  eucalyptol,  or  other  solvents. 
Paraffin  oils  derived  from  different  sources  vary  greatly  in 
their  capacity  for  taking  up  chlorine.  Russian  oils  contain- 
ing much  naphthenes  and  some  American  oils  containing  con- 
siderable quantities  of  olefines  are  unsuitable.  The  best  oils 
with  which  we  are  acquainted  are  those  from  Pennsylvania 
which  have  been  well  purified  with  fuming  sulphuric  acid 
and  then  washed  and  dried.  The  chlorination  of  the  oil  may 
be  conveniently  effected  as  just  described  for  the  eucalyptol. 
It  will  be  found  advisable  to  shake  the  chlorinated  oil  with 
about  one  per  cent  of  animal  charcoal  before  finally  filtering. 
Paraffin  oil  itself  whether  chlorinated  or  not  only  dissolves 
insignificant  traces  of  dichloramine-T. 

Preparation  of  Dichloramine-T  Solutions.  —  The 
constituents  of  the  solutions  are  all  stable  and  may  be  pre- 
served indefinitely  especially  in  colored  bottles.  To  dissolve 
dichloramine-T  in  chlorcosane  it  is  convenient  to  warm  about 
a  quarter  of  the  oil  to  75°  or  80°,  add  the  dichloramine-T 
which  will  promptly  melt,  and  then  stir  in  the  remainder  of 
the  cold  oil.     An  eight  per  cent  solution  thus  prepared  and 


40  A  HANDBOOK  OF  ANTISEPTICS 

kept  in  amber  bottles,  protected  from  excessive  heat,  will 
still  contain  over  seven  per  cent  at  the  end  of  a  month.  An 
accumulation  of  crystalline  deposit,  toluene  sulphonamide, 
in  the  solution  is  evidence  of  decomposition  and  such  solu- 
tions should  be  rejected.  Careful  protection  from  unneces- 
sary exposure  to  light,  heat,  or  moisture  will  do  much  to 
prevent  decomposition.  If  instead  of  chlorcosane,  euca- 
lyptol  be  used  as  solvent,  it  is  ad\dsable  to  dissolve  the  di- 
chloramine-T  (lo  grams)  in  chlorinated  eucal3Aptol  (75  cc.) 
and  then  add  chlorinated  parafhn  oil  (75  cc).  This  mixture 
contains  about  6.5  per  cent  of  dichJoramine-T.  The  propor- 
tion of  paraffin  may  be  reduced  one  half  if  a  stronger  solution 
is  required. 

The  Chemical  Determination  of  the  Concentration 
OF  Chlorine  Antiseptics 

It  is  very  desirable  that  the  concentration  of  solutions  of 
the  various  antiseptics  of  the  chlorine  group  should  be  sub- 
jected to  analytical  control.  This  is  particularly  true  in  the 
case  of  the  hypochlorites  and  other  unstable  products. 

In  principle,  the  same  method  is  used  for  all  the  substances 
mentioned  in  this  chapter.  A  known  quantity  of  the  solution 
or  substance  is  taken  and  an  excess  of  potassium  or  sodium 
iodide  and  of  acetic  acid  is  added.  Iodine  is  at  once  liberated 
in  amount  equivalent  to  the  active  chlorine  of  the  antiseptic, 
and  this  iodine  is  measured  by  determining  the  amount  of  a 
decinormal  solution  of  sodium  thiosulphate  necessary  to 
react  completely  mth  it.  The  following  solutions  are 
required: 

Decinormal  Sodium  Thiosulphate  Solution.  —  This  is  pre- 
pared with  sufficient  accuracy  by  dissolving  24.8  grams  of 
the  pure  crystals  in  water  and  diluting  to  1000  cc.  The 
solution  is  moderately  stable,  especially  if  protected  from 
light,  and  will  serve  for  two  or  three  months. 


ANTISEPTICS  OF  THE  CHLORINE  GROUP  41 

Each  cubic  centimeter  of  this  solution  is  equivalent  to : 

0.0127  gram  Iodine 

0.00354  gram  Chlorine 

0.00262  gram  Hypochlorous  Acid 

0.00372  gram  Sodium  Hypochlorite 

0.01407  gram  Chloramine-T 

0.006      gram  Dichloramine-T 

Iodide  Solution.  —  A  10  per  cent  solution  in  water. 

Acetic  Acid.  —  A  10  per  cent  solution  of  the  pure  acid. 

Starch  Paste.  —  Prepared  by  boiling  about  o.i  gram  starch 
with  100  cc.  of  water,  cooling,  and  allowing  to  sediment. 
The  clear  solution  is  used  as  an  indicator  for  iodine. 

Determination  of  the  ^^ Available  Chlorine"  in  Bleaching 
Powder.  —  A  fair  average  sample  from  bulk  is  taken  and  of 
this  10  grams  is  exactly  weighed  out  into  a  mortar.  The 
powder  is  triturated  in  the  mortar  Vvdth  successive  small 
quantities  of  water  and  comxpletely  transferred  to  a  liter  flask 
which  is  filled  to  the  mark  with  w^ater.  The  whole  is  w^ell 
shaken  and  allowed  to  stand  for  an  hour  or  two.  Ten  cc.  of 
the  supernatant  liquid  is  measured  with  a  pipette  and  trans- 
ferred to  a  small  flask.  Five  cc.  each  of  the  iodide  and  acetic 
acid  solutions  are  then  added.  The  iodine  which  is  now 
liberated  is  determined  by  adding  from  a  burette  the  deci- 
normal  sodium  thiosulphate  solution  until  almost  all  the 
iodine  has  disappeared.  A  few  drops  of  the  starch  paste 
are  then  added  and  the  addition  of  the  thiosulphate  continued 
until  the  blue  color  just  disappears.  The  10  cc.  of  bleaching 
powder  solution  is  equivalent  to  o.i  gram  of  the  solid  sub- 
stance and  as  each  cc.  of  thiosulphate  =  0.00354  gram  avail- 
able chlorine,  the  percentage  of  available  chlorine  in  the 
bleaching  powder  is  found  by  multiplying  the  number  of 
cubic  centimeters  of  thiosulphate  used  by  0.00354  X  1000  = 
3.54.  Thus  if  a  particular  sample  of  bleaching  powder 
treated    as    described    required   9.4    cc.    of    N/io    sodium 


42  A  HANDBOOK  OF  ANTISEPTICS 

thiosulphate,  the  available  chlorine  would  be  33.3  per 
cent. 

Titration  of  Sodium  Hypochlorite  Solutions  or  Eusol.  — 
Ten  cc.  of  the  solution  is  treated  with  5  cc.  each  of  the  iodide 
and  acetic  acid  solutions  and  then  titrated  with  sodium  thio- 
sulphate,  as  described  above.  Each  cubic  centimeter  of 
thiosulphate  used  represents  0.00372  gm.  sodium  hypo- 
chlorite or  0.00262  gm.  hypochlorous  acid.  The  quantity 
of  h}^ochlorite  or  h\^ochlorous  acid  in  100  cc.  will  be  given 
by  multiplying  the  niunber  of  cubic  centimeters  of  thiosul- 
phate used  by  0.0372  or  0.0262  respectively. 

Estimation  of  Chloramine-T  and  Dichloramine-T .  —  These 
substances  are  examined  for  their  content  of  active  chlorine, 
as  described  for  the  hypochlorites  with  the  slight  difference 
that  in  order  to  facilitate  the  reaction  of  the  chloramines 
mth  the  iodide,  it  is  well  to  add  a  little  chloroform  (5-10  cc.) 
or  carbon  tetrachloride  before  titrating.  The  method  of  cal- 
culation follows  from  the  fact  that  each  cubic  centimeter  of 
thiosulphate  used  in  the  titration  is  equivalent  to  0.01407 
gm.  crystallized  chloramine-T  or  0.006  gm.  dichloramine-T. 
It  will  be  noticed  that  one  molecule  of  chloramine-T  liber- 
ates two  atoms  of  iodine  and  one  molecule  of  dichloramine-T 
liberates  four  atoms  of  iodine.  The  reason  for  this  is  that 
each  atom  of  chlorine  in  the  antiseptic  is  equivalent  to  a 
molecule  of  hypochlorous  acid,  each  of  which  liberates  two 
atoms  of  iodine  from  an  acidified  iodide  solution. 

HCIO  H-  2  HI  =  I2  +  HCl  +  H2O 


CHAPTER  III 
THE   PHENOLIC    GROUP   OF   ANTISEPTICS 

Many  of  the  common  antiseptics  belong  to  this  group 
and  have  been  long  employed  for  routine  disinfection  both 
for  surgical  and  hygienic  purposes.  It  cannot  be  said 
that  any  new  properties  of  value  have  been  observed  in 
this  group  as  the  result  of  their  employment  in  war 
surgery. 

Phenol  has  found  steady  advocates  ever  since  Lister 
adopted  it  as  an  aid  in  obtaining  his  brilHant  successes  in 
antiseptic  surgery.  Early  in  the  present  war  the  mistaken 
notion  seemed  to  prevail  that  a  decision  as  to  the  general  utility , 
of  antiseptics  could  be  attained  by  treating  infected  wounds 
receiving  a  minimum  of  prehminary  surgical  treatment  with 
pure  phenol  and  obser\dng  whether  infection  supervened. 
In  the  light  of  present  experience  it  seems  hardly  necessary 
to  say  that  wound  sterilization  cannot  often  be  effected  by  such 
methods.  The  use  of  destructive  coagulants  such  as  phenol 
in  high  concentration  is  undoubtedly  undesirable  and  apt 
to  lead  to  conditions  favorable  to  the  growth  of  anaerobes. 
On  the  other  hand,  phenol  at  a  concentration  of  2.5  to  5  per 
cent  is  still  in  common  use  and  a  mixture  of  equal  parts  of 
one  of  these  solutions  with  hydrogen  peroxide  is  viewed 
with  favor  by  many.  Phenol  and  camphor  when  rubbed 
together  in  equal  proportions  give  a  liquid  which  is  said 
to  give  useful  results  in  infected  cases  of  long  standing.^ 

1  Feldman  and  Walton,  Lancet,  Dec.  3,  1916. 
43 


44  A    HANDBOOK   OF   ANTISEPTICS 

The  stability  of  phenol  solutions  and  their  dean  odor  are 
attractive  qualities  but,  while  phenol  is  undoubtedly  a  good 
disinfectant  for  many  purposes,  it  does  not  seem  to  give  as 
good  results  in  the  treatment  of  badly  infected  wounds 
as  many  other  antiseptics.  The  use  of  alcohol  and  glycerine  ^ 
as  solvents  for  phenol  has  not  much  to  recommend  it,  viewed 
simply  as  regards  disinfection,  since  both  of  these  solvents 
depress  its  germicidal  activity.  Phenol  dissolved  in  vege- 
table oils  is  almost  devoid  of  germicidal  activity  as  but  little 
of  the  antiseptic  leaves  the  fatty  solvent.  Much  weaker 
solutions  dissolved  in  mineral  oil,  in  which  it  is  sparingly 
soluble,  have  been  found  by  Lewis  and  Richards  to  be 
more  effective.  The  fairly  strong  inhibitory  effect  of  phenol 
upon  phagocytosis  has  already  been  referred  to,  although 
it  may  be  doubted  whether  this  is  as  important  a  matter 
as  it  is  sometimes  regarded. 

Anthrax  spores  are  remarkably  resistant  to  phenol  solu- 
tions and  may  be  viable  after  four  days'  immersion  in  a  five 
per  cent  solution.  When  acting  in  the  presence  of  blood 
serum,  defibrinated  blood,  or  pus,  for  reasonable  lengths  of 
time,  e.g.  2  hours,  concentrations  below  2  per  cent  are 
relatively  ineffective  against  pyogenic  cocci.  The  rather 
slow  but  progressive  disinfection  of  a  heavily  infected  mix- 
ture of  blood  serum  and  muscle  extract,  to  which  one  third 
volume  of  2  per  cent  phenol  had  been  added,  is  well 
illustrated  on  p.  86.  Sterilization  was  incomplete  after  22 
hours  although  less  than  i  per  cent  of  the  organism  sur- 
vived. The  way  in  which  phenol  exerts  its  bactericidal 
action  is  not  understood.  Cooper  ^  has  produced  some 
evidence  tending  to  show  that  chemical  reaction  between 
the  bacterial  proteins  and  phenol  is  not  a  sine  qua  non  of 
phenol  disinfection  and  it  is  suggested  that  the  absorption 
of  phenols  by  bacteria  is  merely  the  initial  stage  in  the  pro- 

^  Goodrich,  Brit.  Med.  Journ.,  May  19,  1917. 
2  Biochem.  Journal,  7,  p.  175,  1913. 


THE   PHENOLIC   GROUP   OF   ANTISEPTICS  45 

cess  of  disinfection  and  that  the  germicidal  action  which 
follows  is  due  to  a  de-emulsifying  action  upon  the  colloidal 
suspension  of  some  constituent  protein  essential  for  the 
stability  of  the  organism.  With  phenol  and  its  derivatives 
there  appears  to  be  an  intimate  relation  between  their 
germicidal  powers  and  their  protein  precipitating  capacity. 

Phenol  is  commonly  used  as  a  standard  for  the  measure- 
ment of  the  efhciency  of  disinfectants  by  the  Walker-Rideal 
method  (page  79). 

Various  halogen  derivatives  of  phenol  have  been  proposed 
as  antiseptics  and  while  many  of  them  are  highly  germicidal 
against  bacteria  suspended  in  water,  they  are  not  particularly 
active  in  the  presence,  of  blood  serum  or  other  protein 
material  and  hence  have  little  to  recommend  them  for  wound 
treatment.  A  great  many  of  these  compounds  have  been 
carefully  studied  by  Bechold  and  Ehrhch.^ 

Cresols,  or  methylphenols,  occur  in  three  isomeric  modi- 
fications. They  are  more  actively  germicidal  than  phenol 
itself  and  it  is  stated  that  a  i  per  cent  solution  of  commer- 
cial cresol  in  water  is  as  active  as  3  per  cent  phenol. 
The  commercial  mixture  goes  by  the  name  of  "  tricresol " 
and  is  often  employed  for  sterilization  of  the  hands  and  of 
instruments.  Cresol  paste,  made  with  lanohne  and  white 
wax,  was  recommended  by  Sir.  W.  Watson  Cheyne  ^  and  his 
colleagues  for  the  early  treatment  of  infected  war  wounds, 
but  the  results  obtained  early  in  the  present  war  were  gener- 
ally regarded  as  unfavorable  and  its  use  has  been  discontinued, 

Lysol  is  prepared  by  treating  the  fraction  of  tar-oils 
chiefly  composed  of  cresols  with  fat  and  then  saponifying 
with  alcoholic  soda.  Its  use  for  general  disinfecting  pur- 
poses is  well  known,  but  its  employment  as  a  dressing  for 
wounds  is  limited,  except  in  veterinary  practice.     It  gives 

1  Zeitschr.  f.  physiol.  chcm.,  47,  p.  173,  igo6. 

*  Journ.  Royal  Naval  Medical  Service,  April,  1915.  Lancet,  Nov.  21, 
1914,  Feb.  27,  1915. 


46  A   HANDBOOK   OF   ANTISEPTICS 

a  soapy,  frothing  solution  when  mixed  with  water.  Creolin 
is  a  similar  preparation. 

The  interesting  suggestion  has  been  made  by  Miss  Mary 
Davies^  that  wound  infections  might  be  limited  to  some 
extent  by  the  use  of  antiseptic  substances  for  impregnating 
the  clothing  of  soldiers.  After  studying  the  effect  of  various 
substances  she  concludes  by  recommending  the  use  of  a  5  per 
cent  solution  of  "pyxol,"  a  cresol  and  soft  soap  preparation 
analogous  to  lysol.  It  appears  that  some  bactericidal  power 
is  retained  by  cloth  so  treated  after  a  month's  exposure  to 
sun  and  rain  and  possibly  even  for  a  longer  period.  The 
practical  results  of  these  suggestions  will  be  awaited  with 
interest. 

Thymol,  or  propylmethylphenol,  has  been  recommended 
as  an  antiseptic  for  surgical  purposes  but  has  been  prac- 
tically discarded,  although  dentists  find  its  low  solubility  an 
advantage  in  some  conditions  requiring  antiseptic  treatment. 
Di-iododithymol  is  known  under  the  name  of  aristol.  It  is 
used  to  some  extent  as  a  substitute  for  iodoform  but  is 
unsuited  for  general  use  in  the  treatment  of  war  wounds. 

Salicylic  Acid,  or  orthohydroxybenzoic  acid,  has  received 
much  attention  as  an  antiseptic  for  the  treatment  of  war 
wounds.  In  particular,  a  powdered  mixture  of  salicylic 
acid  and  boric  acid,  introduced  by  Sir  W.  Watson 
Che3me  ^  under  the  name  of  borsal,  was  given  an  ex- 
tended trial.  A  mixture  of  saHcylic  acid  and  borax  had 
been  tried,  with  ineffective  results,  as  a  wound  dressing 
by  the  Japanese  in  the  Russo-Japanese  war.  Borsal  does 
not  seem  to  have  achieved  much  greater  success  in  most 
surgeons'  hands,  and  after  fairly  extensive  trials  in  France, 
either  alone  or  in  conjunction  with  cresol  past,  its  use  was 
abandoned.^    It  appeared  that  borsal  did  not  effectively 

1  Lancet,  Sept.  30,  1916,  p.  603. 

2  Brit.  Med.  Journ.,  May  22,  1915,  p.  912. 

3  Ibid.,  June  5,  1915,  p.  984. 


THE  PHENOLIC   GROUP   OF   ANTISEPTICS  47 

check  sepsis  save  in  superficial  wounds  and  its  use,  in  the 
opinion  of  many,  was  not  unattended  by  danger.  It  seems 
that  the  coagulating  action  of  salicylic  acid  on  blood  and 
wound  exudates  impedes  free  drainage  and  under  these 
conditions,  when  sterilization  has  not  been  complete,  the 
possibilities  for  the  growth  of  anaerobes  such  as  the  gas 
bacillus  and  bacillus  of  malignant  cedema,  are  considerable. 
The  disinfecting  action  of  salicyHc  acid  alone  is  not  great  in 
the  presence  of  wound  exudates  and  is,  moreover,  limited 
by  its  low  solubiHty,  i :  500  in  cold  water.  Addition  of  borax 
causes  a  much  larger  quantity  of  salicylic  acid  to  dissolve 
owing  to  the  formation  of  a  double  salt,  sodium  borosahcy- 
late,  which  is  freely  soluble.  Solutions  of  this  salt  are  used 
to  a  small  extent  as  antiseptic  lotions.  Alcohohc  solutions 
of  sahcyJic  acid  have  been  added  in  small  quantity  to  the 
last  funnel  full  of  sahne  used  for  irrigating  septic  wounds.^ 
In  this  way  the  saHcylic  acid  is  precipitated  by  the  water  and 
may  be  evenly  distributed  over  the  surface  of  the  wound. 
This  method  has  been  found  to  be  preferable  to  dusting  the 
dry  powder  on  the  wound. 

A  large  number  of  halogen  derivatives  of  saUcyhc  acid 
have  been  examined  without  reveaHng  any  particularly 
valuable  qualities,  although  occasionally  their  germicidal 
properties  are  found  to  be  markedly  greater  than  those  of 
salicylic  acid. 

)8-Naphthol  and  Bromonaphthols.  —  The  naphthols 
have  antiseptic  properties  similar  to  those  of  the  simpler 
phenols  but  have  not  been  used  extensively  as  wound  antisep- 
tics, although  /8-naphthol  finds  some  employment  as  an  intes- 
tinal disinfectant  and  is  regarded  as  valuable  in  ointments 
for  the  treatment  of  skin  diseases  of  parasitic  origin.  Recently 
/8-naphthol  has  been  used  as  an  antiseptic  addition  to  the 
paraffin  wax  mixtures  used  in  the  treatment  of  burns.  The 
composition  of  ''ambrine,"  one  of  the  best  known  of  these 
^  L.  Garret  Anderson  and  Helen  Chambers,  Lancet,  June  3,  1916. 


48  A   HANDBOOK   OF   ANTISEPTICS 

mixtures,  has  not  been  disclosed  by  its  proprietary  owners 
but  a  product  made  according  to  the  following  formula,  due 
to  A.  J.  HulV  is  stated  to  give  equally  good  or  better 
results:  /8-naphthol  0.25  per  cent,  eucalyptus  oil  2  per  cent, 
olive  oil  5  per  cent,  hard  paraffin  25  per  cent,  and  soft  paraffin 
67.75  P^^  cent.  The  mixture  may  be  applied  with  a  broad 
camel  hair  brush  or  sprayed  on  at  a  temperature  of  about 
50°  C.  An  illustration  of  the  form  of  spray  used  for  this 
purpose  in  the  naval  service  will  be  found  in  the  British  Med- 
ical Journal,  August  28^,  191 7.  Resorcinol,  0.25-1  per  cent, 
may  be  used  in  place  of  the  /j-naphthol.  The  preparation  of 
the  mixture  is  as  follows :  Melt  the  hard  paraffin,  and  add 
the  soft  paraffin  and  olive  oil.  Add  the  resorcinol  dissolved 
in  half  its  weight  of  absolute  alcohol  and  lastly  add  the 
eucalyptus  oil  when  the  wax  has  cooled  to  about  55°C. 

Becholdt  ^  has  carried  out  experiments  with  a  series  of 
bromine  derivatives  of  y8-naphthol  and  finds  that  several  of 
them  have  germicidal  properties  of  a  high  order  when  tested 
against  pyogenic  cocci  in  water  suspension.  The  tribrom- 
/8-naphthol  in  particular  was  found  to  be  especially  active, 
killing  staphylococci  at  a  dilution  of  i :  250,000.  Our  own 
experiments  have,  however,  indicated  a  materially  lower 
germicidal  value.  This  substance  has  been  made  commer- 
cially and  endorsed  as  an  efficient  antiseptic  agent  for  the 
treatment  of  infected  wounds.  It  is,  however,  not  suitable 
for  military  surgery  as  it  is  very  sparingly  soluble  and  is 
not  significantly  more  active  in  the  presence  of  blood  serum 
than  ordinary  /8-naphthol.  When  dissolved  in  alcohol  and 
tested  against  staphylococci  suspended  in  serum,  the  lethal 
concentration  is  reduced  to  i :  800  or  less. 

Picric  Acid  (trinitrophenol) . — Picric  acid  is  made  use  of 
more  for  the  treatment  of  burns  than  for  ordinary  infected 

1  Brit.  Med.  Journ.,  Jan.  13,  1917. 

2  Zeitschr.  f.  Hyg.  u.  Infekt.  Krankh.,  64,  p.  113,  1909.  Zeitschr.  f.  Angew 
Chem.,  22,  p.  2033,  1909. 


THE   PHENOLIC   GROUP   OF   ANTISEPTICS  49 

wounds.  The  acid  is  soluble  at  room  temperature  in  about 
ninety  parts  of  water  and  dissolves  much  more  readily  in 
alcohol  or  ether.  K  i  per  cent  or  saturated  aqueous  solu- 
tion is  generally  employed  for  surgical  purposes.  As  a 
first  dressing  for  burns  it  has  proved  of  the  greatest  value 
and  does  much  to  relieve  pain  and  reduce  the  risk  of  sub- 
sequent infection.  It  is  employed  either  in  solution  or  as 
impregnated  gauze  or  wool. 

The  use  of  picric  acid  in  the  treatment  of  extensive  wounds 
is  probably  to  be  deprecated,  not  only  because  other  more 
suitable  antiseptics  are  available  but  also  because  the  sub- 
stance is  decidedly  toxic.  The  germicidal  properties  of 
picric  acid  tested  against  staphylococci  or  B.  coli  in  aqueous 
media  are  moderately  high ;  using  the  Walker-Rideal  method 
of  testing,  it  is  found  to  have  a  ''  phenol  coefficient  "  variously 
estimated  between  4  and  6.^  But  picric  acid  is  an  active 
protein  precipitant  and  it  is  unlikely  to  be  capable  of  exert- 
ing very  much  germicidal  action  in  the  presence  of  serum  or 
wound  exudates.  Direct  experiments  in  this  point  appear 
to  be  lacking.  The  coagulating  and  hardening  effect  of 
picric  acid  due  to  the  power  of  precipitating  proteins  is  prob- 
ably responsible  in  part  for  its  successful  use  in  the  treat- 
ment of  burns. 

1  H.  L.  Tidy,  Lancet,  Sept.  11,  1915. 


CHAPTER  IV 
SALTS   OF  THE  HEAVY  METALS   AS  ANTISEPTICS 

The  metallic  salts  which  are  used  because  of  their  anti- 
septic properties  are  mainly  those  of  silver,  mercury,  bismuth, 
and  zinc.  With  one  exception,  namely,  Rutherford  Morison's 
bismuth  paste,  no  very  extended  use  of  these  substances 
has  been  made  in  the  present  war.  In  the  following  chapter, 
their  mode  of  action  will  be  referred  to  first  of  all,  then  their 
germicidal  effects  and,  lastly,  some  of  their  applications. 

The  germicidal  activity  of  many  of  these  metallic  salts, 
when  acting  upon  bacteria  suspended  in  pure  water,  is  ex- 
traordinarily high.  But  this  powerful  action  is  enormously 
reduced  as  soon  as  the  bacteria  are  placed  in  other  media 
than  pure  water.  Most  of  the  soluble  salts  of  these  metals, 
with  the  exception  of  some  colloidal  preparations,  suffer 
from  the  disadvantage  that  they  are  precipi table  by  pro- 
teins or  some  of  the  constituents  of  wound  exudates  such 
as  phosphates,  so  that  their  high  initial  antiseptic  potency 
is  soon  reduced.  It  also  follows  from  this  fact  that  the 
metallic  salts  find  their  most  useful  applications  under 
conditions  which  do  not  lead  to  their  rapid  precipitation, 
and  indeed  under  such  circumstances  they  are  among  the 
most  valuable  disinfectants. 

There  is  a  good  deal  of  evidence  pointing  to  the  belief 
that  the  metallic  ions  present  in  aqueous  solutions  owing  to 
electrolytic  dissociation  are  the  chief  disinfecting  agents  ^  and 

1  Dreser,  Arch.  f.  Exper.  Path.  u.  Pharm.,  32,  p.  456,  1893. 

50 


SALTS   OF    THE   HEAVY   METALS  51 

that  the  undissociated  salts  as  such  are  of  minor  importance. 
Thus  Kronig  and  Paul  found  that  the  disinfecting  action  of 
equimolecular  quantities  of  mercuric  chloride,  bromide,  and 
cyanide  was  in  proportion  to  their  ionic  dissociation  in  solu- 
tion. Miss  Chick  has  shown  that  the  laws  found  to  govern 
other  examples  of  disinfection  are  only  applicable  to  the 
action  of  mercuric  chloride  if  the  concentration  of  Hg" 
ions  is  used  as  the  basis  of  calculation  rather  than  the 
total  concentration  of  the  salt.  The  metallic  ions  are  re- 
sponsible for  the  ordinary  chemical  reactions  of  metallic 
salts  in  aqueous  solution  and  those  metallic  compounds 
which  do  not  yield  the  ordinary  chemical  reactions  for  the 
metals,  such  as  many  protein  and  other  colloidal  prepara- 
tions of  the  metals,  possess  inferior  disinfecting  properties. 
An  interesting  example  of  the  importance  of  the  metallic 
ions  in  disinfection  is  shown  by  the  following  observation  : 
Two  silver  salts  were  compared  as  regards  their  action  on 
staphylococci  in  water  and  blood  serum.  One  of  these 
salts,  silver  fluoride,  which  undergoes  dissociation  with 
formation  of  silver  ions,  killed  in  two  hours  staphylo- 
cocci in  water  at  a  concentration  of  less  than  i :  10,000,000. 
The  other  salt  was  the  double  cyanide  of  silver  and  sodium 
which,  on  solution  in  water,  gives  few  if  any  metallic  ions 
but  remains  in  solution  as  a  complex  aggregate.  When 
tested  against  staphylococci  in  water,  the  lethal  concentra- 
tion was  only  about  i  :  5000.  Thus  it  will  be  seen  that  silver 
fluoride  solution  containing  metallic  ions  is,  under  the  con- 
ditions of  the  experiment,  two  thousand  times  as  active  as 
silver  sodium  cyanide  which  gives  few  or  no  metallic  ions. 
When  the  same  salts  were  tested  against  staphylococci 
suspended  in  blood  serum,  the  lethal  concentrations  were 
much  more  closely  approximated,  being  about  i  :  7000  and 
1 :  3000  respectively.  It  appears  probable  that  the  metallic 
ions  of  the  salts  exert  their  disinfecting  action  by  reacting 
chemically   with   the  protein   or   other   constituent   of   the 


52  A   HANDBOOK   OF   ANTISEPTICS 

bacterial  protoplasm,  and  indeed  in  some  cases  this  phenom- 
enon has  been  actually  observed.  Salts  of  the  heavy  metals, 
even  when  present  in  a  nutrient  medium  in  extremely  small 
amount,  are  capable  of  exerting  an  inhibitory  influence  upon 
the  growth  of  bacteria,  so  that  in  all  estimations  of  the  germi- 
cidal action  of  these  salts  it  is  essential  to  avoid  carrying 
over  any  of  the  antiseptic  into  subcultures.  In  addition 
to  the  inhibitory  action  upon  the  growth  of  bacteria  exer- 
cised by  traces  of  metallic  salts.  Miss  Chick  ^  has  noted  another 
phenomenon  exhibited  by  this  class  of  disinfectant.  ''  If 
bacteria  are  subjected  to  the  action  of  i  :  looo,  i :  10,000  or 
even  weaker  solutions  of  mercuric  chloride,  there  is  an  in- 
terval during  which  some  at  least  of  them  may  be  resusci- 
tated by  the  timely  administration  of  an  antidote  (in  this 
case  a  sulphide  solution),  but  if  this  antidotal  treatment  is 
not  employed,  no  amount  of  subsequent  dilution  beyond 
the  limits  when  inhibition  occurs,  can  prevent  the  death 
of  the  organism.  It  would  seem  that  the  mercuric  salt  has 
been  already  absorbed  by  the  bacteria  and  possibly  formed 
some  combination  with  its  substance,  not  however  to  a 
sufficient  extent  to  prevent  recovery  if  a  large  excess  of  the 
sulphide  solution  be  employed."  In  one  case  it  was  observed 
that  in  a  24-hour  culture  of  B.  paratyphosus  some  individuals 
at  least  were  able  to  manifest  vitality  after  contact  with 
5  per  cent  mercuric  chloride  solution  for  four  minutes,  pro- 
vided ammonium  sulphide  was  promptly  applied  as  antidote. 
There  is  an  extensive  literature  dealing  with  the  germi- 
cidal action  of  the  metallic  salts,  but  most  of  the  results 
are  not  comparable  with  one  another  owing  to  variations 
in  the  technique  employed  in  making  the  tests.  Even  slight 
variations  in  the  composition  of  the  medium  in  which  these 
substances  act  produce  enormous  variations  in  the  results 
of  the  experiments.  Thus  we  have  found  the  apparent 
activity  of  mercuric  chloride  against  staphylococci  in  a 
1  Journ.  of  Hygiene,  8,  p.  92,  igo8. 


SALTS   OF    THE   HEAVY   METALS  63 

hard  tap  water  to  be  only  one  fifth  of  that  sho\\Ti  when 
distilled  water  was  employed,  while  with  silver  salts  the 
results  are  even  more  liable  to  variation.  The  following 
extracts  from  published  experiments  are  given  simply  as  a 
rough  guide  to  antiseptic  potency,  but  for  details,  the  original 
papers  must  be  consulted. 

The  use  of  mercuric  chloride  as  a  disinfectant  practically 
dates  from  Robert  Koch's^  experiments  published  in  1881. 
Somewhat  later,  Geppert  showed  that  Koch  had  overes- 
timated the  antiseptic  value  of  the  salt  through  error  in  tech- 
nique involving  the  carrying  over  of  mercury  salts  into 
subcultures.  Geppert's  experiments  were  adversely  criti- 
cized by  von  Behring^  but  have  been  essentially  substan- 
tiated by  subsequent  workers.  The  action  of  mercuric 
chloride  upon  spores,  especially  those  of  B.  anthracis,  has 
been  most  carefully  studied  by  Kronig  and  Paul,'^  Madson 
and  Nyman,^  and  Miss  Chick.  °  A  chart  from  i\Iiss  Chick's 
paper,  in  which  the  figures  are  taken  from  Kronig  and 
PauFs  experiments,  gives  a  good  idea  of  the  general  character 
of  the  results,  though  many  more  details  \Yii\  be  found  in 
the  original  papers. 

As  exem.plifying  the  action  of  mercuric  chloride  on  a  vege- 
tative form,  B.  paratypJwsus,  the  following  chart  is  repro- 
duced from  Miss  Chick's  paper. 

The  action  of  mercuric  chloride  upon  bacteria  is  not  nearly 
so  rapid  as  is  commonly  thought  to  be  the  case.  Miss  Chick 
found  that  B.  paratyphosus  could  withstand  the  action  of 
five  per  cent  bichloride  for  four  minutes,  and  staphylococcus 
aureus,  for  fifteen  minutes,  if  at  once  treated  with  a  sulphide 
antidote. 

But  these  experim.ents  relate  only  to  the  action  of  the 
antiseptic  on  suspensions  of  organisms  in  an  aqueous  medium. 

*  Ueber  Desinfection,  Mittheil.     Kaiserl.  Gesenclheitsamt,  Vol.  I. 

2  Zeitschr.  f.  Hygiene,  0,  p.  396,  1890.  3  Ji)id.^  25,  p.  i,  1897. 

*  Ihid.,  57,  p.  388,  1907.  ^  Journ.  of  Hygiene,  8,  p.  92,  1908. 


54 


A   HANDBOOK   OF   ANTISEPTICS 


When  working  in  a  blood  serum  medium,  its  activity  is  much 
reduced,  while  in  the  presence  of  whole  blood,  pus,  or  muscle 


CHART  I 


4000 
3500 
3000 
2500 
2000 
1500 
1000 
500 

c 

o  , 

> 

\ 

V 

o  \ 

I 

t 

X 

"®^-> 

''■< 

:--- 

' -i 

>■ T 

> < 

10 


20  30  4b  50 

Time  in  minutes 


60 


Illustrating  the  results  of  Kronig  and  Paul's  experiment.  Continuous  curve, 
disinfection  of  anthrax  spores  with  2.1  per  1000  HgCU.  Dotted  curve, 
disinfection  of  anthrax  spores  with  i.i  per  1000  HgCb. 

extract  much  higher  concentrations  are  required  for  effec- 
tive action.  A  single  new  experiment  may  be  quoted 
to  illustrate  this  (see  p.  87  ).  Mercuric  chloride  (i  cc. 
1 :  1000)  was  added  to  blood  serum  (i  cc.)  and  50  per  cent 
muscle  extract  (i  cc.)  previously  heavily  inoculated  with 


SALTS   OF    THE   HEAVY   METALS 


56 


CHART  II 


P4 

CXI 

w 


;-u' 

Oo 

— e — — 

« 

"50  Too  150  200        250 

Time  in  minutes 

Times  taken  for  disinfection  of  B.  paralyphosus  with  varying  concentrations 
of  mercuric  chloride,  HzS  being  used  as  antidote. 


56  A   HANDBOOK   OF   ANTISEPTICS 

staphylococcus  aureus.  The  final  concentration  of  mer- 
curic chloride  was  therefore  i :  3000.  The  number  of  sur- 
viving organisms  was  estimated  at  varying  intervals  of  time> 
The  experiment  was  conducted  at  32°  C.  Although  at  the 
end  of  five  minutes  almost  90  per  cent  of  the  organisms 
were  killed,  the  mixture  was  not  sterilized  completely  at  the 
end  of  three  hours. 

Among  other  salts  of  mercury  that  are  employed  for  surgical 
purposes,  are  mercury  potassium  iodide,  cyanide,  oxycyanide 
and  double  zinc  cyanide.  "Mercuric  biniodide,"  i.e.  mer- 
curic potassium  iodide,  resembles  mercuric  chloride  closely  in 
germicidal  properties  but  is  regarded  as  less  irritating.  The 
other  salts  mentioned  are  less  active  under  most  conditions. 

The  germicidal  action  of  most  silver  salts  closely  resembles 
that  of  the  corresponding  mercuric  compounds.  Silver 
chloride  is  insoluble  and  hence  ineffective,  but  silver  nitrate 
appears  to  resemble  mercuric  chloride  fairly  closely.  Its 
action  on  B.  paratyphosus  has  been  quantitatively  studied 
by  Miss  Chick  with  results  that  resemble  the  curve  given 
on  p.  55.  Silver  cyanides,  colloidal  silver,  and  various 
organic  compounds  which  yield  few  silver  ions  on  solution 
in  water  all  appear  to  have  inferior  germicidal  properties, 
although  some  of  them  find  useful  application  in  civil  prac- 
tice. For  their  preparation,  properties,  and  uses,  reference 
must  be  made  to  textbooks  of  pharmacology. 

Experiments  on  the  action  of  silver  nitrate  solution  and 
argyrol  on  considerable  quantities  of  staphylococci  and 
other  organisms  suspended  in  equal  parts  of  blood  serum 
and  muscle  extract  are  recorded  on  p.  87.  Silver  nitrate 
(i  per  cent)  added  so  that  the  final  concentration  was 
0.33  per  cent  killed  about  95  per  cent  of  the  organisms 
in  six  hours  but  failed  to  sterilize  completely  in  24  hours. 
Argyrol  with  a  final  concentration  of  5  per  cent  did  sterilize 

1  Potassium  sulphide  was  added  as  "  antidote  "  to  prevent  the  carrying  over 
of  active  mercury  salts  to  the  subcultures. 


SALTS   OF   THE   HEAVY   METALS  67 

in  24  hours  but  many  organisms  were  still  present  at  the 
end  of  six  hours. 

The  salts  of  bismuth  do  not  appear  to  have  been  examined 
very  carefully  as  regards  their  bactericidal  action,  although 
their  action  in  checking  undesirable  fermentations  in  beer 
worts  was  discovered  long  ago.  Most  normal  bismuth  salts 
are  more  or  less  rapidly  decomposed  by  water  with  formation 
of  insoluble  basic  salts,  and  some  of  these  have  found  effec- 
tive use  as  mild  antiseptics  capable  of  slow  but  prolonged 
action. 

Zinc  salts  have  long  been  known  to  have  antiseptic  prop- 
erties and  the  chloride  especially  has  been  used  by  Lister, 
Kocher,  and  others.  Its  germicidal  action  is  far  inferior 
to  that  of  most  mercury  or  silver  salts.  A  5  per  cent 
solution  is  ineffective  against  anthrax  spores  but  a  2.5  per 
cent  solution  is  reported  effective  against  most  vegetative 
forms  in  a  reasonably  short  time,  when  acting  in  an  aqueous 
medium.  Its  activity  is  however  much  influenced  by  the 
medium  in  which  it  acts,  since  it  is  very  readily  precipitated 
by  proteins,  phosphates,  etc.  An  experiment  in  which  3 
per  cent  zinc  chloride  was  added  to  a  mixture  of  equal 
parts  of  blood  serum  and  muscle  extract  inoculated  with 
staphylococci  and  other  organisms,  so  that  the  final  con- 
centration of  zinc  chloride  was  i  per  cent,  showed  that  about 
one  sixth  of  the  organisms  survived  at  the  end  of  an  hour 
and  a  half  and  that  complete  sterilization  was  not  quite 
accomplished  after  24  hours  (p.  88). 

Uses  of  Metallic  Salts  in  War  Surgery.  —  The  prac- 
tical uses  of  the  metallic  disinfectants  in  the  treatment 
of  infected  war  wounds  has  not  been  extensive  with  the  ex- 
ception of  a  paste  containing  bismuth  subnitrate  which  will 
be  referred  to  later.  Mercury  salts  alone  have  almost  no 
advocates,  although  a  certain  amount  of  gauze  impregnated 
with  Lister's  double  cyanide  of  mercury  and  zinc  is  still  em- 
ployed, with  the  object  of  preventing  re-infection  of  the  wound 


58  A   HANDBOOK   OF   ANTISEPTICS 

and  in  the  hope  of  controlHng  further  progress  of  the  existing 
infection.  A  preparation  of  mercuric  chloride  and  malachite 
green  introduced  by  Fildes,  Rajchman,  and  Cheatle  has, 
however,  given  useful  results,  especially  in  chronic  suppurat- 
ing wounds.  An  account  of  this  preparation  will  be  found 
in  the  section  on  dyes  (p.  6i). 

Silver  nitrate  at  i  :  looo  was  tried  for  some  time,  but  the 
darkening  of  the  treated  wounds  on  exposure  to  light  was  a 
drawback  and  the  results  appeared  to  be  only  moderately 
good,  so  that  at  the  present  time  it  is  scarcely  used  at  all. 

Zinc  salts  have  a  marked  caustic  and  coagulant  action 
and,  as  is  well  known,  are  frequently  employed  on  account 
of  these  effects  on  torpid  ulcerations,  fistulous  tracts,  etc. 
Lister  long  ago  made  use  of  zinc  chloride  solution  in  many 
infected  conditions  and  noted  the  fact  that  the  precipitation 
of  zinc  compounds  in  the  coagulated  surface  of  the  wound 
was  generally  sufl&cient  to  prevent  recurrence  of  sepsis. 
Strong  solutions  of  zinc  chloride,  up  to  as  high  as  lo  per  cent, 
were  believed  useful,  particularly  by  Belgian  surgeons,  when 
used  as  wet  dressings  on  wounds  which  had  been  freely 
incised  subsequent  to  the  development  of  gas  gangrene  infec- 
tion. This  treatment,  which  is  a  drastic  one,  has  been  largely 
supplanted  by  irrigation  v/ith  some  form  of  hypochlorite 
solution. 

By  far  the  most  useful  metallic  salt  antiseptic  so  far  em- 
ployed in  the  present  war  is  the  bismuth  paste  introduced 
by  Rutherford  Morison.^  This  is  made  by  mixing  bismuth 
sub  nitrate  (i  part)  and  iodoform  (2  parts)  with  sufficient 
liquid  parafhn  oil  to  make  a  thick  paste  of  such  consistence 
that  it  may  be  readily  spread  in  a  thin  layer  with  the 
help  of  a  spatula  or  spoon.  This  mixture,  which  is  com- 
monly known  as  "  B.  I.  P.,"  was  first  of  all  recommended  for 
the  treatment  of  infected  war  wounds  in  which  suppura- 
tion was  already  established.     But  it  is  now  used  to  a  con- 

1  Lancet,  Aug.  12,  1916,  p.  268. 


SALTS   OF    THE   HEAVY   METALS  59 

siderable  extent  for  the  treatment  of  fresh  wounds,  partly 
owing  to  its  ease  of  apphcation  and  the  fact  that  frequent 
redressing  is  usually  unnecessary,  although  adequate  pro- 
vision must  be  made  for  free  drainage.  When  casualties 
are  unusually  numerous  and  speed  of  treatment  becomes 
of  great  practical  importance,  the  paste  is  said  to  be  particu- 
larly useful. 

The  method  of  using  the  paste  for  suppurating  wounds 
is  essentially  as  follows :  After  appropriate  surgical  treat- 
ment, the  wound  cavity  and  surrounding  skin  is  carefully 
mopped  with  alcohol.  The  wound  is  then  filled  with  the 
paste,  and  dressed  with  gauze  which  is  covered  with  an 
absorbent  pad,  which  in  turn  is  held  in  position  with  stick- 
ing plaster  and  a  bandage.  This  dressing  requires  no  change 
for  days  or  weeks  if  the  patient  is  free  from  pain  and  con- 
stitutional disturbances.  Should,  however,  discharge  come 
through  the  dressing,  the  stained  part  must  be  soaked  in 
alcohol  and  a  fresh  gauze  dressing,  wet  with  alcohol,  apphed 
as  a  further  covering.  In  order  to  redress  the  wound,  wool 
soaked  in  alcohol  is  used  to  wipe  away  the  sticky,  dirty 
looking  discharge.  The  wound  and  a  small  area  of  skin 
is  again  plastered  with  paste  and  this  in  turn  covered  with 
gauze  dressing,  pad,  and  bandage,  as  before. 

It  is  claimed  that  the  results  following  the  use  of  this 
paste  are  notably  good  in  fractures  of  the  long  bones,  and  the 
ease  of  dressing  as  well  as  its  infrequency  and  the  absence 
of  pain  are  valuable  features. 

Precise  bacteriological  analysis  of  the  effects  of  the  paste 
upon  infected  wounds  has  not  yet  been  supplied,  so  that 
final  judgment  as  to  the  bactericidal  value  of  the  mixture 
must  be  delayed.  It  must  not  be  forgotten  that  the  con- 
stituents of  the  mixture  are  not  innocuous  and  that  iodoform 
poisoning,  particularly  when  the  drug  is  placed  in  closed 
cavities,  is  not  uncommon.  However,  iodoform  poisoning 
seems  to  be  very  rarely  encountered  with  the  present  mixture. 


60  A   HANDBOOK   OF   ANTISEPTICS 

The  paste  appears  to  be  very  slowly  absorbed  and  may  cause 
disturbance  long  after  apparent  healing  of  the  wound.  A 
small  sinus  may  form  and  iodoform  suspended  in  a  brownish 
fluid  may  escape,  but  the  exit  wound  heals  promptly.  In 
the  majority  of  cases,  however,  it  is  slowly  absorbed  and  by 
means  of  X-rays  the  slow  disappearance  of  B.I.  P.  in  bone 
cavities,  etc.,  can  be  readily  followed. 


CHAPTER  V 
DYES  AS  ANTISEPTICS 

A  LARGE  number  of  dyestuffs  possess  germicidal  properties, 
although  until  recently  they  have  been  employed  for  the 
destruction  of  blood  parasites  such  as  trypanosomes  rather 
than  bacteria. 

Malachite  green,  used  in  conjunction  with  mercuric  chloride, 
was  recommended  early  in  191 5  in  a  report  to  the  Medical 
Research  Committee,  by  Fildes,  Rajchman,  and  Cheatle,^ 
and  has  been  used  fairly  extensively,  especially  in  the  naval 
service.  A  2  per  cent  solution  of  malachite  green  in  80  per 
cent  pure  alcohol  is  mixed  with  an  equal  volume  of  a  2  per 
cent  solution  of  mercuric  chloride  in  80  per  cent  alcohol.  The 
two  solutions  are  best  kept  apart  until  needed  for  use. 
The  mixture,  as  Micklethwaite  has  shown,  contains  a  double 
compound  consisting  of  one  molecule  of  malachite  green  and 
two  molecules  of  mercuric  chloride.  This  compound  ap- 
pears to  be  readily  dissociated  in  contact  with  the  tissues. 
The  malachite  green  is  reduced  by  living  tissues  to  the  leuco- 
compound  and  therefore  becomes  invisible  in  a  wound  but 
may  still  maintain  its  activity.  Sloughs  and  necrosed  tis- 
sue, however,  do  not  reduce  the  dye.  The  mixture  is  gen- 
erally applied  by  means  of  a  spray  and  is  surprisingly  non- 
irritating  when  the  concentration  of  the  mercury  salt  is 
considered.  It  has  been  found  particularly  useful  as  a  skin- 
disinfectant  and  for  the  treatment  of  superficial  wounds,  but 
it  has  also  proved  of  value  in  cases  of  osteomyelitis,  septic 

1  Lancet,  1915,  ii,  p.  165. 
61 


62  A  HANDBOOK  OF  ANTISEPTICS 

fractures,  and  burns.  Experiments  on  the  germicidal  effect 
of  malachite  green  when  acting  on  organisms  either  in  a 
blood  medium  or  blood  serum-muscle  extract  (p.  89)  lead 
us  to  the  conclusion  that  the  value  of  the  dye  as  a  wound 
antiseptic  probably  has  been  much  overestimated.  Media 
such  as  those  noted,  to  which  malachite  green  had  been  added 
to  a  1 :  1000  concentration,  readily  underwent  putrefaction. 
These  conclusions,  however,  simply  refer  to  the  dye  itself  and 
not  to  its  compound  with  mercuric  chloride  as  employed  by 
Cheatle  and  his  colleagues. 

Malachite  green  belongs  to  the  group  of  triphenylmethane 
dyes  and  may  be  represented  by  the  following  formula: 

/\ 


(CH3)2N  <^\— C— <^>  N(CH3)2 

OH 

It  may  be  prepared  by  a  variety  of  methods,  one  of  which, 
due  to  Doebner,^  consists  in  heating  dime  thy  laniline  (2 
mols.)  with  zinc  chloride  and  benzo trichloride  (i  mol.). 
The  zinc  salt  obtained  by  this  method  is  commonly  con- 
verted into  the  oxalate  which  is  the  usual  commercial 
form  of  malachite  green.  Browning  has  shown  that  some 
oxalates  of  dyestuff s,  including  malachite  green  and  brilliant 
green,  are  more  harmful  to  phagocytosis  than  other  salts, 
so  that  it  might  be  desirable  to  employ  some  soluble  salt  of 
malachite  green  other  than  the  oxalate  for  antiseptic  purposes. 
Certain  other  members  of  the  triphenylmethane  group  of 
dyes  are  known  to  possess  definite  bactericidal  action,  as 
shown  by  Dreyer,  Kriegler,  and  Walker.^    Hexamethyl  violet, 

1  Liebigs  Annalen,  217,  p.  250.        2  journ.  Path,  and  Bact.,  is,  p.  133,  1910. 


DYES   AS   ANTISEPTICS  63 

also  known  as  "crystal  violet,"  hexaethyl  violet,  and  brilliant 
green  are  all  credited  with  marked  germicidal  properties. 
The  latter  dye  has  been  used  to  some  extent  by  Browning 
and  his  surgical  colleagues.  Our  own  experiments  do  not 
indicate  that  brilliant  green  is  nearly  so  powerful  a  germicide 
as  claimed  by  Browning  (cp.  pp.  90,  95),  although  it 
doubtless  may  be  of  value  in  the  treatment  of  certain  types 
of  wounds.  A  particularly  exuberant  growth  of  bright  red 
granulation  tissue  is  observed  to  follow  its  use.  Brilliant 
green  or  tetraethyldiaminotriphenylcarbinol  has  a  constitu- 
tion similar  to  that  of  malachite  green  but  with  ethyl 
groups  replacing  the  methyl  groups  of  the  latter.  It  is 
prepared  like  malachite  green  by  heating  diethylaniline  with 
zinc  chloride  and  benzotrichloride. 

AcRiFLAViNE,  Trypaflavine,  OR  Flavine.  —  This  sub- 
stance was  first  prepared  by  Benda^  at  Ehrlich's  instigation 
in  191 1  and  was  found  to  have  a  marked  therapeutic  effect 
on  trypanosome  infections.  The  systematic  narne  for  the 
compound  is  3-6  diamino-io-methyl-acridinium  chloride  and 
is  represented  by  the  following  formula : 


H2N\/\/\/NH2 

/N\ 
CH3     CI 

The  preparation  of  the  compound  was  protected  by  patents 
and  the  registered  trade  mark  "  trypaflavine  "  was  assigned  to 
it.  In  order  to  avoid  this  name  Browning  and  his  colleagues 
used  the  simple  term  "flavine,"  but  as  a  vegetable  yellow  dye 
of  the  same  name  has  long  been  known  this  designation  was 

1  Ber.  deutsch.  Chem.  Gesell.,  45,  p.  1787,  1912. 


64  A   HANDBOOK   OF   ANTISEPTICS 

unfortunate.  To  avoid  these  and  other  important  technical 
difficulties  the  Medical  Research  Committee  has  recom- 
mended^ that  so  far  as  Britain  is  concerned  the  substance 
should  be  officially  known  as  "acriflavine"  and  under  this 
name  various  firms  have  obtained  licenses  to  manufacture 
it.2  In  this  way  monopoly  from  the  exploitation  of  the 
substance  under  fancy  names  has  been  obviated. 

Acrifiavine  has  been  claimed  by  Browning  and  his  associ- 
ates ^  to  be  a  most  powerful  antiseptic  and  it  has  found 
application  in  the  prophylactic  treatment  of  fresh  wounds  as 
well  as  in  cases  where  suppuration  has  developed.  It  has 
also  been  employed  in  the  disinfection  of  the  nasopharynx 
of  carriers  of  the  meningococcus.  Our  own  experiments  on 
the  germicidal  action  of  acrifiavine  lead  us  to  regard  it  as 
distinctly  more  active  under  most  conditions  than  either  mala- 
chite green  or  brilliant  green  (p.  97),  though  its  rate  of 
disinfection  is  decidedly  slow.  Direct  observations  on  the 
bacterial  count  of  infected  wounds  treated  with  i :  1000 
acrifiavine  confi,rm  our  belief  that  the  germicidal  action 
of  the  substance  has  been  overestimated. 

One  of  the  most  remarkable  properties  of  acrifiavine  is 
chat  its  germicidal  action  is  apparently  enhanced  by  admix- 
ture with  serum,  though  greatly  diminished  by  pus.  Relative 
to  its  bactericidal  power,  the  dye  is  less  detrimental  to  phago- 
cytosis than  most  other  antiseptics  and  it  has  but  little  in- 
jurious action  on  the  tissues,  but  on  the  other  hand  its 
germicidal  action  is  exerted  decidedly  more  slowly  than 
that  of  some  commoner  antiseptics.  Its  solutions  may  be 
boiled  and  can  even  be  heated  to  120°  in  the  autoclave. 
It  is  generally  used  in  i :  1000  solution  in  0.8  per  cent 
salt  solution  and  may  be  employed  for  swabbing  or  syringing 
septic  wounds  once  or  twice  daily  according  to  the  acuteness 

1  Brit.  Med.  Journ.,  June  9,  1917,  p.  769. 

2  Acrifiavine  is,  we  believe,  being  manufactured  by  Messrs.  Boot,  Island  St., 
Nottingham,  and  doubtless  by  other  firms. 

3  Brit.  Med.  Journ.,  Jan.  20,  1917,  p.  73. 


DYES   AS   ANTISEPTICS  66 

of  the  condition.  Gauze  soaked  in  the  solution  may  be 
placed  next  the  wound  and  a  protective  covering  put  over  the 
whole  to  hinder  evaporation.  Several  ounces  of  i  :  looo 
acriflavine  solution  may  safely  be  left  in  the  tissues  or  peri- 
toneal cavity.  It  may  also  be  injected  with  a  serum  syringe 
into  infiam.matory  areas.  The  opinion  has  been  expressed 
that  the  special  uses  of  acriflavine  for  particular  purposes 
have  still  to  be  defined  in  relation  to  other  antiseptics  and 
to  the  operative  m_ethods  of  surgery,  to  which  it  can  be  at 
best  only  a  valuable  aid. 

The  following  table,  taken  from  Browning's  paper,  con- 
tains the  results  of  bacteriological  tests  made  mth  the 
various  dyes  mentioned.  In  judging  of  these  results  it 
must  be  borne  in  mind  that  relatively  very  small  numbers 
of  bacteria  were  employed  (o.i  cc.  of  a  i :  20,000  dilution 
in  saline  of  a  24-hour  peptone  water  culture)  and  that  the 
action  of  the  antiseptics  was  allowed  to  continue  for  24  to  48 
hours  before  examination.^  A  loopful  of  the  mixture  before 
adding  the  acriflavine  is  stated  to  yield  twenty  or  more 
colonies.  Such  a  low  concentration  of  organisms  in  an  old 
wound  would  indicate  approaching  surgical  sterihty,  and 
moreover  a  survival  of  any  number  less  than  5  per  cent 

1  In  the  original  paper  by  Browning  and  his  colleagues  certain  antiseptics 
of  the  chlorine  group,  e.g.  chloramine-T,  eusol,  chlorine  water,  and  Dakin's 
solution,  are  included  and  an  attempt  is  made  to  determine  what  is  termed  "  anti- 
septic potency"  as  expressed  by  the  ratio : 

Lethal  concentration  in  serum  of  the  substance  in  question 

Lethal  concentration  in  serum  of  chloramine-T 

These  experiments  are  valueless  since  the  chlorine  antiseptics  were  added  first 
to  media,  cither  peptone,  water,  or  serum,  which  in  the  dilutions  employed 
promptly  decomposed  most  of  them.  For  such  experiments  it  is  essentialto 
add  the  disinfectant  last,  as  in  practical  use,  and  there  is  Httle  value  in  continuing 
experiments  with  rapid-acting  unstable  chlorine  antiseptics  for  more  than  a  few 
hours.  The  experiments  as  described  give  a  false  impression  of  the  relative  po- 
tency of  acriflavine  and  similar  dyes.  The  original  statements  by  Dakin,  Cohen, 
Kenyon,  and  Daufresne  as  to  the  germicidal  action  of  hypochlorites  and  chlora- 
mine-T in  water  and  serum  have  been  repeatedly  confirmed  by  ourselves  and 
many  others. 


66 


A   HANDBOOK   OF   ANTISEPTICS 


of  the  organisms  in  the  test  would  have  a  good  chance 
of  being  overlooked.  As  already  stated,  our  own  tests  with 
heavily  infected  mixtures  indicate  much  feebler  germicidal 
action  than  that  shown  in  the  following  table. 


Antiseptic 

Staphylococcus  Aureus 
Lethal  Concentration 

Bacillus  Coli 

Communis,  Lethal 

Concentration 

Concentra- 
tion Which 
Inhibits 
Phagocy- 
tosis 

In  Peptone 
Water  0.7  % 

In  Serum 

In  Peptone 
Water  0.7  % 

In  Serum 

Malachite 

green 
(oxalate  and 

sulphate) 
Brilliant 

green 
(sulphate) 
Crystal 

violet 
Acriflavine 

I  :  10,000,000 

I  :  10,000,000 
1 :  4,000,000 
1 :  20,000 

1 :  40,000 

I  :  30,000 
1 :  400,000 
1 :  200,000 

I  :  20,000 

1 :  130,000 
1 :  8000 
1 :  1300 

I  :  1000 

1 :  3500 
1 :  8000 
I  :  100,000 

1 :  7000 

1 :  2000 
1 :  7000 
1 :  500 

The  preparation  of  acriflavine  on  a  moderately  large  scale 
requires  a  considerable  degree  of  chemical  skill.  Several 
methods  for  the  synthesis  of  acriflavine  and  related  acridine 
derivatives  ^  are  known  but  only  one  of  them  need  concern 
us  here.  The  working  details  must  be  sought  in  the 
original  communication.^ 

Aniline  and  formaldehyde  unite  to  give  a  polymeric  sub- 
stance, anhydroformaldehyde-aniline  (i) .  When  heated  with 
aniline  hydrochloride  it  undergoes  a  curious  rearrangement 
with  the  formation  of  p-diaminophenylmethane  (2).  This 
substance  is  nitrated  with  nitric  and  sulphuric  acids  so  as  to 
give  a  dinitro  derivative  (3) ;    which  in  turn  is  reduced  with 

1  Bucherer's  Chemie  der  Tierfarbstoffe,  1914,  may  be  consulted  for  informa- 
tion concerning  the  synthesis  of  acridine  derivatives. 

2Benda,  Ber.  deutsch.  Chem.  Gesel.,  45,  p.  1787,  1912;  D.  R.  Patents,  Kl. 
22b,  230412  and  243085,  Casella  and  Co-,  1911-1912. 


DYES   AS   ANTISEPTICS 


67 


tin  and  hydrochloric  acid.  On  heating  the  reaction  mixture 
in  an  autoclave  to  135°,  3-6-diamino  acridine  is  obtained  (4). 
In  order  to  obtain  the  methyl  derivative  the  latter  compound 
is  first  converted  into  its  di-acetyl  compound  to  protect 
the  amino-groups  and  then  treated  in  nitrobenzene  solution 
at  175°  with  the  methyl  ester  of  toluene  sulphonic  acid. 
The  product  is  then  hydrolyzed,  when  acriflavine  (hydrochlo- 
ride) =  3-6-diamino-io-methylacridine  (5)  results : 


N:CH, 


CH. 


►HoN 


(i) 


CH2 


►H2N  i\     JNN 
\/  O2O 

(3) 


NH 


->H2N 


NHs 


CH 


Apparently  the  germicidal  properties  of  acriflavine  are 
shared  by  a  number  of  other  acridine  derivatives  and  one  of 
these,  diaminoacridine,  (4)  is  easier  and  cheaper  to  manufac- 
ture and  appears  to  be  equally  desirable.  It  will  be  known 
as  "proflavine."  A  detailed  publication  on  this  substance 
is  expected  shortly.  Experiments  on  its  germicidal  action 
are  included  in  Chapter  VII. 


CHAPTER  VI 
MISCELLANEOUS  ANTISEPTICS 

In  this  section  brief  reference  will  be  made  to  a  few  anti- 
septics which  cannot  be  included  in  preceding  sections.  It 
will  be  impossible  to  treat  these  substances  systematically, 
and  instead  brief  notes  as  to  the  chief  characteristics  of  the 
substances  is  all  that  will  be  attempted. 

Hydrogen  Peroxide  and  other  Peroxides.  —  Hydro- 
gen peroxide  is  not  held  in  very  high  repute  as  a  germicide 
but  it  has  certain  other  qualities  which  render  it  decidedly 
valuable.  When  tested  against  relatively  small  quantities 
of  staphylococcus  aureus  or  B.  pyocyaneus  in  water,  a 
concentration  of  0.03  per  cent  actual  H2O2,  i.e.  a  i  per 
cent  dilution  of  the  pharmacopoeal  product,  may  suffice  to 
sterilize  in  two  hours,  while  in  blood  serum  about  double  this 
concentration  may  be  necessary.  But  these  conditions  are 
entirely  artificial  and  unrelated  to  what  happens  when 
hydrogen  peroxide  is  applied  to  a  septic  wound.  Blood, 
pus,  and  muscle  juice  contain  an  enzyme  ''catalase"  which 
rapidly  brings  about  the  decomposition  of  hydrogen  peroxide 
with  liberation  of  gaseous  oxygen.  This  rapid  decomposition 
with  evolution  of  gas  soon  decomposes  all  the  peroxide  and 
its  disinfecting  action  comes  to  a  speedy  end.  The  mechanical 
effect  of  the  disengagement  of  gas  is  often  a  valuable  prop- 
erty and  is  made  use  of  in  loosening  sticky  secretions, 
washing  away  pus,  or  loosening  adherent  dressings.  For 
such  purpose  it  is  of  great  value  but  it  is  important  that 
its  transient  germicidal  effect  should  be  recognized. 

68 


MISCELLANEOUS   ANTISEPTICS  69 

A  great  variety  of  other  peroxides  have  been  put  forward 
as  disinfectants,  but  most  of  them  are  of  doubtful  practical 
value.  Two  of  the  most  active  of  these  substances  are  the 
benzoyl  hydrogen  peroxide  and  benzoyl  acetyl  peroxide  dis- 
covered by  Baeyer  and  studied  by  Freer  and  Novy.  The 
latter  compound  has  been  used  to  some  extent  but  the  un- 
stable character  of  both  the  substance  and  its  solutions 
has  prevented  its  extensive  employment.  Dibenzoyl  per- 
oxide has  been  recommended  as  an  antiseptic  but  it  is  a 
sparingly  soluble,  practically  indifferent  compound  of  no 
significant  germicidal  value. 

Ozone.  —  This  substance  has  recently  been  used  by 
Stoker  ^  for  the  treatment  of  infected  wounds,  especially 
cavities  and  sinuses  in  bone  injuries.  An  Andreoli  ozonizer 
is  used  to  produce  the  ozonized  air  which  is  allowed  to  act 
for  about  fifteen  minutes  or  such  shorter  period  as  pro- 
duces a  superficial  glazing  of  the  wound  surfaces.  De- 
tails of  ozone  concentration  and  bacteriological  controls 
are  not  yet  available,  although  the  results  are  stated  to 
be  good  and  the  formation  of  excessive  granulation  tissue  is 
avoided. 

Iodine.  —  Extensive  use  is  made  of  iodine  as  a  germicide. 
Its  action  is  powerful  and  prompt  when  the  conditions  are 
such  that  the  antiseptic  has  free  excess  to  the  microorganisms. 
Ampoules  containing  tincture  of  iodine  have  been  used 
largely  in  the  present  war  as  a  first  aid  treatment  to  be 
applied  by  the  wounded  soldier.  In  general  the  results  as 
regards  the  prevention  of  sepsis  have  been  disappointing, 
mainly  it  would  appear  because  the  injured  man  is  not 
apt  in  most  cases  to  put  the  iodine  where  it  can  reach  the 
focus  of  infection.  The  presence  of  much  blood  and  pro- 
longed oozing  are  of  course  inimical  to  the  exercise  of 
germicidal  action.  Usually  little  more  is  accomplished 
than  a  fair  cleansing  of  the  adjacent  skin. 

1  Lancet,  Oct.  21,  p.  712,  1916. 


70  A   HANDBOOK   OF   ANTISEPTICS 

The  use  of  iodine  as  a  skin  disinfectant  introduced  by 
Stretton^  in  1909  is  widely  practiced  and  undoubtedly  it  has 
great  value  for  this  purpose.  A  2.5  per  cent  solution  is  usually 
strong  enough  and  alcohol  is  generally  employed  as  the 
solvent.  Seventy  per  cent  alcohol  is  preferable  to  stronger 
spirit  and  it  is  important  to  use  pure  alcohol  as  otherwise 
iodoacetone  and  other  products  are  apt  to  be  formed,  which 
are  very  irritating  to  the  eyes  of  the  operator. 

Light  petroleum  and  heavy  mineral  oils  are  also  used  as 
solvents  for  iodine  and  act  well.  They  have  the  advantage 
of  being  stable  and  cheap.  Dichlorethylene  {i.e.  acetylene 
dichloride)  has  also  been  proposed  but  is  much  more  ex- 
pensive. 

The  use  of  iodine  for  the  antiseptic  treatment  of  large 
war  wounds  is  now  practiced  much  less  frequently  than 
before,  although  it  was  given  a  thorough  trial  in  the  early 
days  of  the  war.  It  has  been  found  much  too  irritating  for 
repeated  application  and  not  infrequently  objectionable  after 
effects  such  as  severe  neuritis  have  been  observed.  Its 
strong  coagulating  action  on  proteins  is  also  an  objection- 
able feature.  In  general  it  may  be  said  that  iodine  will  be 
found  most  useful  when  the  conditions  are  such  that  rapid 
and  complete  sterilization  may  be  effected  by  a  single  appli- 
cation as  in  skin  disinfection  or  small  surface  wounds. 

An  experiment  illustrating  the  rapid  effect  of  2  per  cent 
iodine  solution  on  staphylococci  and  other  organisms  sus- 
pended in  a  blood  serum-muscle  extract  medium  will  be 
found  on  p.  86.  A  i  per  cent  solution  added  to  an  equal 
volume  of  blood  heavily  infected  with  streptococci  did  not 
kill  all  the  organisms  in  one  hour  according  to  Emery. 
Against  staphylococci  suspended  in  water,  about  ten  million 
per  cubic  centimeter,  i :  100,000  iodine  is  effective  in  two 
hours,  while  in  blood  serum  i :  1000  is  required,  according 
to  our  own  observations. 

1  Brit.  Med.  Journ.,  Aug.  14,  1909,  May  22,  1915. 


MISCELLANEOUS   ANTISEPTICS  71 

Borates,  Perborates,  and  Boric  Acid.  —  These  sub- 
stances while  possessing  almost  negligible  germicidal  prop- 
erties find  extensive  use  when  a  bland,  mildly  antiseptic 
lotion  is  required.  Sodium  monoborate  is  a  rather  strongly 
alkaline  salt  but  is  said  to  be  non-irritating  to  wounds ; 
borax,  or  sodium  biborate  is  less  strongly  alkahne,  while 
boric  acid  is  feebly  acid.  All  of  these  substances  are  used 
for  restraining  the  growth  of  putrefactive  organisms  rather 
than  for  disinfection  in  the  true  sense.  Sodium  perborate  is 
prepared  by  adding  hydrogen  peroxide  to  borax  solutions 
and  is  stable  when  preserved  in  the  dry  state.  It  is  often 
used  as  a  convenient  substitute  for  hydrogen  peroxide. 

Persulphates. — The  use  of  potassium  or  sodium  persul- 
phate has  been  advocated  but  actually  their  disinfecting  action 
on  pyogenic  organisms  is  feeble.  A  solution  of  the  sodium 
salt  has  been  regarded  by  some  as  useful  for  stimulating  the 
rate  of  cicatrization  of  wounds,  though  this  action  can  hardly 
be  regarded  as  satisfactorily  demonstrated. 

Acids.  —  Almost  all  acids  possess  some  germicidal  action 
and  generally  speaking  their  activity  is  proportional  to  their 
"  strength."  Just  as  metallic  "  ions  "  appear  to  be  the  actual 
disinfecting  agent  when  metallic  salts  are  employed,  so  in 
the  case  of  most  acids  it  is  the  hydrogen  ions  which  seem  to 
be  effective.  Extensive  experiments  on  this  subject  have 
been  carried  out  by  Bial  ^  and  by  Winslow  and  Lockridge.^ 
A  few  experiments  on  the  action  of  various  acid  substances 
on  B.  typhosus  will  be  found  on  p.  114. 

Occasionally  acids  have  been  employed  in  wound  treatment 
and  it  has  been  thought  that  irrigation  with  weak  lactic  acid 
was  useful  in  inhibiting  the  growth  of  the  gas  bacillus  in 
infected  wounds,  but  the  treatment  has  not  met  with  general 
favor. 

1  Archiv.  exper.  Path.  a.  Pharm.,  38,  p.  i,  1897.  Zeitschr.  f.  physiol.  Chem., 
40,  p.  51,3,  1902. 

'^  Journ.  of  Infectious  Diseases,  3,  p.  547,  1906. 


72 


A   HANDBOOK   OF   ANTISEPTICS 


Alcohol  and  Ether.  —  Both  of  these  substances  are 
employed  in  the  treatment  of  infected  wounds  but  they  are 
used  as  much  for  the  help  they  afford  in  the  mechanical  clean- 
ing of  dirty  wounds  as  for  any  direct  germicidal  action. 
Most  vegetative  forms  of  bacteria  may  be  killed  fairly 
readily  by  50  per  cent  alcohol  but  alcohol  of  much  lower 
or  higher  strength  is  less  effective,  while  most  spores  are  un- 
affected by  alcohol  of  any  strength.  The  following  table 
contains  the  results  of  experiments  by  Minervini  ^  to  deter- 
mine the  time  required  to  kill  various  organisms  in  alcohol 
of  varying  concentration.  Koch's  ''thread"  method  of 
testing  the  viability  of  the  organisms  was  used  and  the 
results  are  at  least  comparable  among  themselves. 


Organism 


Staphylococcus  aureus 
B.  pyocyaneus  .  .  . 
M.  prodigiosus       .     . 

B.  coli 

B.  sub  tills  (spores) 
B.  anthracis  (spores) 


Dilution  of  Alcohol 


25% 


12-24  hours 

under  i  hour 

I  hour 

24  hours 


50  %         70  %  80  % 


10  min. 
10  min. 
10  min. 
I  hour 


10  mm. 

10  min 

I  hour 

all  Uving  after  8  days 

all  U\dng  after  50  days 


living  after 

6  hours 

6  hours 

Uving  after 


99% 


3  days 
12  hours 
1 2-24  hours 
24  hours 


It  is  well  known  that  alcohol  or  glycerol  materially  reduces 
the  germicidal  efficiency  of  some  antiseptics,  particularly 
those  of  the  phenol  class.  Kronig  and  Paul  found  that 
phenol  dissolved  in  98  per  cent  alcohol  was  devoid  of  bac- 
tericidal action  when  tested  against  spores.  Cooper  ^  has 
correlated  this  fact  with  a  diminished  protein  precipitating 
action  of  alcoholic  phenol  when  contrasted  with  aqueous 
phenol,  but  whatever  the  explanation  may  be  it  is  clear  that 
alcohol  is  not  a  desirable  solvent  for  phenolic  disinfectants. 

^Cp.,  Rideal,  Disinfection  and  Disinfectants,  p.  322. 
2  Biochem.  Journ.,  7,  p.  175,  1913. 


MISCELLANEOUS  ANTISEPTICS  73 

The  germicidal  properties  of  ether  have  recently  been  ex- 
amined by  Topley,^  who  finds  that  the  vapors  possess  a 
slight  but  definite  action.  An  exposure  to  ether  vapors  of 
one  to  forty-eight  hours  was  necessary  to  sterilize  agar  slants 
on  which  pyogenic  organisms  were  growing.  Liquid  ether 
was  irregular  in  its  action  and  good  contact  with  the  organ- 
isms was  difficult  to  secure.  It  is  clear,  however,  from 
these  and  from  clinical  results  that  any  beneficial  effects 
following  the  use  of  ether  in  the  treatment  of  septic  infec- 
tions is  not  due  to  direct  disinfection.^ 

FoR]VL4LDEHYDE.  —  The  physical  and  chemical  properties 
of  formaldehyde,  which  is  obtainable  in  commerce  as  a  40 
per  cent  solution  known  as  "formalin,"  make  it  valuable 
for  various  forms  of  disinfection,  such  as  the  fumigation  of 
roomxS,  etc.  But  so  far  as  the  treatment  of  septic  wounds  is 
concerned  it  has  not  proved  particularly  successful  and  is 
now  scarcely  used  for  such  purposes.  It  is  employed  to 
some  extent  for  the  sterilization  of  the  hands  and  instru- 
ments but  it  is  less  popular  than  formerly.  A  0.5  per  cent 
solution  is  generally  employed  for  such  purposes.  It  is  not 
a  very  rapid  acting  disinfectant  and  when  tested  in  the  or- 
dinary way  under  the  standard  conditions  it  has  a  phenol 
coefficient  of  about  0.4,  but  if  the  time  of  action  is  prolonged 
its  activity  m.ay  be  somewhat  greater  than  that  of  phenol. 

Hexamethylenetetiiamine.  —  This  substance,  obtained 
by  the  action  of  ammonia  on  formaldehyde,  has  but  little  di- 
rect germicidal  action.  In  acid  solution  it  may  be  decom- 
posed with  liberation  of  formaldehyde  which  can  thus  exert  its 
antiseptic  action.  A  large  number  of  derivatives  of  hexa- 
methylenetetramine  have  been  prepared  by  Jacobs  and 
Heidelberger  and  many  of  these  are  more  powerful  than 
the  parent  substance,  but  their  useful  application  has  still 
to  be  defined.     Hexamethylenetetramine  itself  is  not   suit- 

1  Brit.  Med.  Journ.,  Feb.  6,  1915- 

2  Cp.  Distaso  and  Bowcn,  Brit.  Med.  Journ.,  Feb.  24,  1917. 


74  A   HANDBOOK   OF   ANTISEPTICS 

able  for  wound  treatment  since  under  these  conditions  its 
germicidal  action  is  quite  inadequate. 

Iodoform.  —  The  use  of  iodoform  in  combination  with 
bismuth  subnitrate  and  parafhn  oil  in  the  mixture  known  as 
"B.  I.  P."  has  already  been  referred  to  on  p.  58.  The  sub- 
stance was  once  considered  to  be  a  powerful  antiseptic  but 
this  is  no  longer  believed  to  be  the  case.  Microorganisms 
may  flourish  in  contact  with  iodoform  but,  on  the  other  hand, 
it  is  not  disproved  that  in  contact  with  living  tissues  iodoform 
may  be  slowly  decomposed  with  the  formation  of  products 
of  genuine  antiseptic  value.  Apart  from  the  paste  referred 
to,  its  use  in  surgery  is  diminishing,  probably  on  account  of 
occasional  unpleasant  poisoning  effects  that  may  follow  its 
free  use,  especially  in  confined  cavities.  Many  odorless  sub- 
stitutes for  iodoform  are  known  under  various  trade  names, 
but  in  general  their  action  appears  to  be  similar  to  that  of 
iodoform  itself. 

Permanganates.  —  The  potassium  salt  is  principally  used 
for  irrigation,  i :  1000,  in  gonorrhoea.  It  is  an  active  germi- 
cide under  conditions  not  involving  rapid  decomposition 
by  excess  of  organic  matter.  All  the  permanganates  are 
strong  oxidizing  agents  and  as  soon  as  they  are  reduced  to 
manganese  salts  their  disinfecting  action  ceases,  so  that 
their  maximum  germicidal  effects  are  transitory.  They  are 
unsuitable  for  septic  wound  treatment  on  account  of  their 
rapid  reduction  but  have  many  other  useful  applications. 

Quinine.  —  The  hydrochloride  of  this  alkaloid  has  been 
recommended  by  Kenneth  Taylor  ^  as  a  dressing  for  sep- 
tic wounds,  especially  those  infected  with  the  B.  (srogenes 
capsulatus.  The  substance  is  used  in  o.i  per  cent  aqueous 
solution  with  the  addition  of  o.i  per  cent  hydrochloric  acid 
or  I  per  cent  alcohol  to  inhibit  precipitation  of  the  base. 
Tested  in  vitro  Taylor  finds  that  it  is  about  ten  times  as  ef- 
fective as  phenol  against  the  gas  bacillus  although,  on  the 

1  Lancet,  Sept.  4,  1915.     Brit.  Med.  Journ.,  Dec.  25,  1915. 


MISCELLANEOUS   ANTISEPTICS  75 

Other  hand,  it  is  used  on  wounds  in  much  lower  concentra- 
tion than  is  usual  with  phenol.  Serum  or  pus  is  stated  to 
have  no  very  marked  action  in  reducing  the  germicidal 
activity  of  quinine.  The  solution  is  used  either  as  a  wet 
dressing  or  for  continuous  drip  instillation.  A  curious  fact 
noted  by  Taylor  in  connection  with  the  use  of  quinine  is 
that  while  there  appears  to  be  a  decrease  in  B.  cero genes 
capsulatus  infection  there  was  a  progressive  increase  in  the 
appearance  of  B.  pyocyaneus,  and  laboratory  tests  showed 
that  the  latter  organism  was  the  most  resistant  to  quinine 
of  the  common  pyogenic  bacteria. 

An  endeavor  has  been  made  to  utilize  the  combined  an- 
aesthetic and  antiseptic  properties  of  mixtures  of  quinine  and 
urea  for  wound  treatment,  but  this  has  failed  to  secure  much 
favor. 

Chinosol.  —  This  compound  was  originally  considered  to 
be  potassium  oxyquinoline  sulphonate  or  a  double  salt  of 
this  with  potassium  sulphate,  but  is  now  stated  to  be 
neutral  oxyquinoline  sulphate.  It  possesses  a  strong  inhib- 
itory action  on  the  growth  of  many  microorganisms  and 
failure  to  recognize  this  fact  fully  led  to  exaggerated  claims 
as  to  its  germicidal  potency.  A  full  report  upon  this  sub- 
stance has  been  made  by  the  Council  on  Pharmacy  and 
Chemistry  of  the  American  Medical  Association.^  The 
general  conclusions  arrived  at  are  essentially  as  follows :  As 
regards  staphylococcus  aureus  and  B.  typhosus  chinosol  is 
more  strongly  antiseptic  than  phenol  and  about  equal  to 
mercuric  chloride,  but  as  a  germicide  in  watery  solution  it  is 
somewhat  inferior  to  phenol  and  vastly  inferior  to  mercuric 
chloride.  In  acid  broth  the  findings  were  still  less  favorable 
to  chinosol. 

These  conclusions  make  it  doubtful  if  much  direct  germi- 
cidal effect  on  wounds  can  follow  its  application,  though  it 
is  possible  that  the  substance  might  find  useful  employment 

1  Cp.  Journ.,  Am.  Med.  Assoc,  May  28,  1910. 


76  A   HANDBOOK   OF   ANTISEPTICS 

as  a  wound  dressing  with  the  object  of  restraining  the 
growth  of  organisms  and  preventing  reinfection.  It  does 
not  appear  to  have  been  used  extensively  in  the  present 
war. 

AcETANiLiDE  AND  ITS  DERIVATIVES.  —  This  substance  has 
often  been  recommended  as  an  antiseptic/  but  our  own  ex- 
periments have  shown  its  germicidal  properties  when  tested 
against  moderate  quantities  of  staphylococci  to.  be  so  low  that 
it  can  hardly  exert  any  effective  disinfection  in  wounds.  A 
half  per  cent  solution  failed  to  sterilize  staphylococci  in  water 
in  two  hours,  while  in  blood  serum  its  antiseptic  action  is 
negligible.  Recently  E.  F.  Greene  ^  has  revived  the  ques- 
tion of  its  possible  use  in  infected  war  wounds,  applied  as  a 
dry  powder,  but  this  can  hardly  be  endorsed,  not  only  on 
account  of  its  poor  antiseptic  action  but  also  because  symp- 
toms of  poisoning  have  been  stated  to  follow  its  use.  Its 
free  application  to  extensive  wounds  would  certainly  not  be 
without  danger  to  many  individuals  who  are  fairly  susceptible 
to  this  drug. 

Various  derivatives  of  acetanilide  in  which  the  hydrogen 
of  the  benzene  ring  has  been  replaced  by  chlorine,  bromine, 
or  iodine  have  been  advocated  as  antiseptics  from  time  to 
time.  Parabromacetanilide  is  sometimes  known  under  the 
name  of  "  asepsin  "  or  "  antisepsin  "  and  is  stated  to  have 
anodyne  properties.  Our  own  experience  indicates  that 
none  of  these  derivatives  are  sufhciently  active  disinfectants 
to  be  of  value  in  wound  treatment. 

1  Cp.  Beck,  New  York,  Med.  Journ.,  March  19,  1893. 

2  Brit.  Med.  Journ.,  May  29,  1915,  p.  928. 


CHAPTER  VII 
METHODS  OF  TESTING  ANTISEPTICS 

The  testing  of  substances  for  their  antiseptic  and  germicidal 
power  is  fraught  with  innumerable  pitfaUs.  It  is  possible 
to  take  almost  any  substance  and  by  carefully  choosing  the 
conditions  under  which  it  acts,  make  it  appear  to  possess 
germicidal  potency,  and  conversely,  it  is  equally  possible  to 
take  valuable  germicides  and  by  observing  their  action 
under  unreasonable  conditions,  make  them  appear  inert. 
The  necessity  for  choosing  methods  of  testing  in  some  de- 
gree in  conformity  with  the  mode  of  use  of  the  substance 
and  under  conditions  not  too  rem_ote  from  those  under  which 
it  is  proposed  to  employ  it,  is  of  fundamental  importance. 

The  simplest  conditions  are  presented  in  the  determination 
of  the  lethal  concentration  of  a  germicide  acting  upon  micro- 
organisms suspended  in  water.  The  chief  variables  in  such 
a  determination  are  the  number  of  organisms  taken  for 
each  experiment,  and  the  temperature  and  time  of  action. 
With  regard  to  the  number  of  organisms,  it  is  desirable  to 
use  a  fairly  large  quantity,  partly  because  spontaneous  death 
of  the  bacteria  then  becomes  less  of  a  factor  and  also  because 
the  test  becomes  a  more  rigid  one.  In  general,  some  such 
concentration  as  a  hundred  million  bacteria  to  the  cubic 
centimeter  will  be  found  appropriate.  The  effect  of  tem- 
perature on  the  rate  of  disinfection  has  already  been  con- 
sidered, also  the  speed  of  action  will  be  found  to  vary 
enormously  with  different  substances  and  with  varying 
media. 

77 


78  A   HANDBOOK  OF   ANTISEPTICS 

One  of  the  oldest  methods  used  for  the  determination  of 
lethal  concentrations  is  the  so-called  'thread"  method 
devised  by  Koch.  Sterile  raw  silk  thread  cut  into  portions 
about  a  centimeter  long  are  soaked  in  a  broth  culture  or 
aqueous  suspension  of  the  required  organisms  and  then  dried. 
These  threads  are  soaked  for  an  arbitrary  time  in  varying 
concentrations  of  the  antiseptic,  then  removed  and  trans- 
ferred to  sterile  broth,  which  on  incubation  will  show  whether 
or  not  the  organisms  were  killed.  One  of  the  main  objections 
to  this  method  is  the  mechanical  carrying  over  of  adhering 
antiseptic  into  the  broth  medium,  so  that  inhibition  of  growth 
frequently  occurs  even  though  the  organisms  are  not  killed, 
and  the  substance  appears  to  be  a  more  effective  germicide 
than  is  actually  the  case.  Failure  of  the  antiseptic  to 
promptly  penetrate  to  all  parts  of  the  thread  may  lead  to 
erroneous  estimates  of  its  germicidal  power. 

A  later  method,  which  is  often  called  the  '^ garnet"  method, 
was  worked  out  by  Kronig  and  Paul.  Garnets  of  equal  size 
are  dipped  in  an  emulsion  of  the  organism  —  usually  spore- 
bearing  anthrax  bacilli  —  and  then  carefully  dried  so  that 
a  thin  film  of  organisms  is  spread  over  their  surface.  The 
garnets  are  then  immersed  in  a  solution  of  the  antiseptic, 
which  after  a  definite  time  is  gently  washed  away  and  the 
garnets,  if  need  be,  treated  with  an  antidote  such  as  am- 
monium sulphide  when  mercury  disinfectants  are  employed. 
The  garnets  are  then  shaken  with  water  to  detach  a  fairly 
constant  proportion  of  the  organisms  and  an  aliquot  part  of 
the  fluid  is  plated  in  solid  media  for  counting.  An  alternative 
method  using  the  surface  of  nutrient  agar  instead  of  garnets 
or  thread,  is  described  by  Bechold  and  Ehrlich.^ 

But  neither  the  "  thread  "  nor  "  garnet "  method  is  often 
used  now  and  the  simpler  method  is  usually  employed  of 
mixing  known  but  varying  quantities  of  the  disinfectant  with 
a  constant  concentration  of  organisms  and  subculturing  from 

1  Zeit.  physiol.  Chem.,  47,  p.  177,  1906. 


METHODS   OF   TESTING   ANTISEPTICS  79 

the  mixture  into  broth  or  agar  at  known  intervals  of  time,  in 
order  to  determine  whether  disinfection  has  been  completed. 
An  application  of  this  method,  which  is  of  great  value  in 
standardizing  and  comparing  different  substances  with 
regard  to  their  practical  uses  as  disinfectants  in  hygienic 
work,  is  that  devised  by  Walker  and  Rideal  ^  in  1 903 .  By  this 
procedure  it  is  possible  to  express  the  value  of  a  disinfectant 
in  terms  of  a  numerical  ratio  using  pure  phenol  as  a  standard. 
The  original  method  is  substantially  as  follows :  a  definite 
amount  (usually  5  drops)  of  a  24-hour  broth  culture  of  the 
organism  selected,  e.g.  B.  typhosus  or  B.  coli,  is  added  to  5 
cc.  of  solutions  of  varying  concentration  of  the  disinfectant. 
Subcultures  are  taken  at  intervals  of  2  J  minutes  up  to  15 
minutes  to  determine  the  point  of  complete  sterility.  A 
similar  series  of  tests  is  made  with  a  standard  phenol  solu- 
tion of  such  strength  that  sterilization  of  the  organisms  will 
be  effected  within  the  time  limits  of  2  J  to  15  minutes.  The 
necessary  concentration  of  phenol  will  usually  be  about  0.8 
per  cent  with  most  cultures  of  B.  typhosus.  By  comparing 
the  concentration  of  the  disinfectant  which  just  effects 
sterilization  in  a  given  time  with  the  phenol  concentration 
which  also  effects  sterilization  in  the  same  time,  an  estimate 
is  formed  of  the  germicidal  potency  of  the  substance  under 
investigation.  Thus  if  a  concentration  of  i :  600  of  a  par- 
ticular substance  is  as  effective  under  the  above  conditions 
and  in  the  same  time  as  i :  120  phenol,  the  ''phenol  coefficient " 

will   be  or  5.      It  is  an  essential  and   important   fea- 

120 

ture  of  this  method  that  time  of  action  should  be  constant 
while  the  concentration  of  the  disinfectant  is  varied.  The 
reverse  conditions,  namely,  fixed  concentration  and  variable 
time,  may  lead  to  entirely  erroneous  inferences  as  to  ger- 
micidal potency. 

1  Journ.  Roy.  Soc.  Inst.  24,  p.  424,  1903.     Later  details  concerning  the  Walker- 
Rideal  method  will  be  found  in  The  Amer.  Journ.  Pub.  Health,  Vol.  3,  No.  6. 


80  A   HANDBOOK   OF   ANTISEPTICS 

The  determination  of  the  "  phenol  coefficient "  of  a  substance 
furnishes  most  valuable  information,  but  chiefly  as  regards 
the  relative  value  of  disinfectants  to  be  used  in  fairly  homo- 
geneous aqueous  media.  Chick  and  Martin  ^  and  many 
others  cited  in  the  paper  by  these  authors  have  sought  to 
obtain  a  more  practical  estimate  of  the  germicidal  value  of 
disinfectants  by  adding  organic  matter  of  various  kinds 
to  the  bacterial  suspension.  For  some  types  of  general 
disinfectants  the  addition  of  a  definite  quantity  of 
dried  feces  is  recommended,  for  example,  when  testing 
those  substances  destined  to  be  used  for  the  disinfection 
of  stools. 

The  problem  of  selecting  conditions  for  studying  the  action 
of  substances  to  be  used  as  wound  disinfectants  is  much 
more  difficult.  Useful  information  is  obtained  by  determin- 
ing the  lethal  concentration  of  substances  acting  on  organ- 
isms suspended  in  blood  serum  or  in  blood,  or  by  studying 
their  action  on  pus.  Certain  precautions  must  be  taken 
in  working  with  these  media.  With  all  of  them,  it  is  of  course 
essential  that,  as  in  practical  use,  the  antiseptic  solution 
should  be  added  to  the  mixtures  last,  for  in  many  cases  if 
this  is  not  done  totally  erroneous  results  will  be  obtained. 
It  has  happened  with  extraordinary  frequency  that  small 
quantities  of  labile  chlorine  antiseptics  have  been  added  to 
organic  media  and  then  at  unstated  intervals  after  all  or 
most  of  the  antiseptic  has  been  destroyed,  the  mixture  is 
infected  with  organisms  which  naturally  grow  unchecked. 
Under  such  conditions,  what  is  really  being  observed  is  less 
the  germicidal  action  of  the  antiseptic  than  the  rate  of 
chemical  reaction  which  has  taken  place  between  the  unstable 
antiseptic  and  organic  media.  The  results  of  such  a  pro- 
cedure are  naturally  particularly  misleading  when  high 
dilutions  of  antiseptic  are  employed  in  experiments  to  de- 
termine the  lethal  concentration. 

1  Journ.  Hygiene,  8,  p.  654,  1908. 


METHODS   OF    TESTING   ANTISEPTICS  81 

A  great  advantage  in  the  use  of  serum  is  the  fact  that  it 
presents  a  homogeneous  medium  of  fairly  constant  com- 
position ;  but  it  is  important  to  bear  in  mind  that  many  or- 
ganisms, e.g.  B.  paratyphosus,  are  very  susceptible  to  the  ac- 
tion of  blood  serum  even  though  previously  heated  to  58- 
60°  for  an  hour.  To  avoid  this  complication,  liberal  quanti- 
ties of  an  organism  such  as  staphylococcus  aureus,  which  is' 
fairly  resistant  to  serum,  should  be  used.  When  substances 
of  high  germicidal  power  are  examined  for  the  determination 
of  the  lethal  concentration,  and  hence  low  concentrations  are 
employed,  it  will  usually  be  found  sufficient  to  carry  out  the 
tests  in  a  medium  containing  50  per  cent  or  even  less  of 
serum,  since  its  mass,  relative  to  that  of  the  antiseptic,  will 
be  very  large. 

The  testing  of  the  germicidal  effects  of  substances  acting 
on  organisms  suspended  in  blood  would  seem  the  rational 
procedure  for  examining  compounds  which  might  be  used 
intravenously.  A  blood  medium  has,  however,  been  sug- 
gested as  a  standard  method  of  testing  ordinary  antiseptics 
by  Emery.^  The  use  of  a  blood  medium  as  a  standard  is 
particularly  adverse  to  the  hypochlorite  antiseptics  which 
rapidly  react  with  haemoglobin  so  that  a  relatively  con- 
siderable amount  of  the  former  must  be  added  before  any 
active  antiseptic  will  persist  in  the  mixture.  For  these 
tests  use  rpay  be  made  of  reconstituted  blood  obtained  by 
mixing  serum  with  cells  separated  from  citrated  blood,  al- 
though for  most  purposes  defibrinated  blood  or  citrated 
blood  itself  v/ould  probably  serve.  The  technique  em- 
ployed by  Emery  is  substantially  the  following  :  Nine  parts  of 
"reconstituted  blood"  is  mixed  with  one  part  of  a  strep- 
tococcus culture  containing  about  250,000,000  organisms  per 
cubic  centimeter.  One  volume  of  the  infected  blood  is  mixed 
on  a  slide,  using  a  marked  capillary  pipette,  with  an  equal 
volume  of  the  antiseptic  solution.    The  mixture  is  then  drawn 

1  Lancet,  April  15,  1916,  p.  817. 


82 


A   HANDBOOK   OF   ANTISEPTICS 


into  the  pipette,  which  is  sealed  and  incubated  and  subse- 
quently examined  to  determine  whether  the  contents  are 
sterile  or  whether  viable  organisms  persist.  It  should  be 
noted  that  apparently  the  concentrations  of  antiseptic  quoted 
iri  Emery's  table  refer  to  the  strength  of  the  solution  added, 
so  that  their  actual  concentration  in  the  final  mixture  is  half 
of  that  given. 


Antiseptic 


Phenol 

Eusol  (HCIO)     .     . 
Sodium  Hypochlorite 
Mercuric  Chloride  . 
Mercury  Biniodide 

Iodine 

Lysol 

Malachite  Green     . 


IS  Minutes 


Did  not  kill        Killed 


1 :  70 

[i :  400?] 
[i  :  200?] 
I  :  100 
I  :  60 
I  :  100 
I  :  40 
I  :  250 


1 :  60 


80 
40 

? 

30 
200 


60  Minutes 


Did  not  kill        Killed 


1 :  60 


100 

60 

100 

150 

250 


50 


1:80 
1 :  40 

? 
1 :  120 
1 :2oo 


The  results  recorded  by  Emery  do  not  make  the  method  as  de- 
scribed by  him  appear  particularly  accurate,  since  with  only 
one  exception  as  high  a  concentration  was  necessary  to  steri- 
lize the  mixture  in  60  min.  as  in  15  min.,  although  the  act 
of  disinfection  is  a  progressive  time  reaction.  Moreover,  a 
higher  concentration  of  phenol  is  recorded  as  necessary  to 
sterilize  in  sixty  minutes  than  is  stated  to  be  effective  in 
fifteen.  But  the  use  of  blood  as  a  medium  for  studying  the 
germicidal  action  of  substances  in  the  presence  of  cellular 
elements,  is  of  distinct  value  since,  unlike  pus,  its  compo- 
sition is  fairly  uniform.  The  blood  should  be  heavily  in- 
fected with  organisms  so  that  its  natural  bactericidal  proper- 
ties will  not  effect  the  end  result  materially.  On  pp.  93,  95 
a  number  of  experiments  with  antiseptics  of  the  chlorine 
group  and  dyestuffs,  acting  on  staphylococci  in  blood  media, 
are  recorded. 


METHODS   OF   TESTING   ANTISEPTICS  83 

The  determination  of  the  disinfecting  action  of  substances 
upon  pus  is  obviously  important  as  bearing  on  the  treatment 
of  suppurating  wounds.  As  already  stated,  the  disinfection  of 
pus  is  difficult  of  accomplishment  and  relatively  high  concen- 
trations of  antiseptic  are  necessary.  But  great  difficulties 
are  encountered  in  laboratory  experiments  on  the  disinfection 
of  pus  owing  to  the  enormous  variations  in  its  physical  con- 
dition and  the  number  of  organisms  it  contains  and  whether 
these  organisms  are  mainly  free  or  ingested  in  the  leucocytes. 
Rous  and  Jones  ^  have  shown  that  living  phagocytes  are  able 
to  protect  ingested  organisms  from  the  action  of  substances 
such  as  potassium  cyanide  in  the  surrounding  fluid  and  even 
from  the  action  of  a  strong  homologous  antiserum,  and  they 
obtained  evidence  that  this  protection  by  phagocytes  was 
largely  conditioned  on  their  being  alive.  But  even  when 
all  the  leucocytes  are  dead,  there  are  considerable  mechanical 
difiiculties  in  securing  good  contact  with  the  antiseptic 
solution.  An  interesting  series  of  experiments  on  the  steri- 
lization of  pus  by  various  antiseptics  is  recorded  in  a  paper 
by  Parry  Morgan,^  and  some  of  the  results  have  already  been 
cited  on  p.  8. 

Thus  far,  we  have  considered  almost  exclusively  the  ques- 
tion of  the  lethal  concentration  of  disinfectants  acting  under 
different  conditions,  but  it  is  becoming  constantly  more 
evident  that  much  more  than  this  is  needed  in  judging  of 
the  utility  of  antiseptics.  As  already  stated  on  p.  6,  the 
act  of  disinfection  resembles  in  many  respects  an  ordinary 
chemical  reaction  in  which  the  two  reacting  components  are 
represented  by  disinfectant  and-  bacterial  protoplasm.  Now 
the  rate  of  disinfection  varies  enormously  with  different 
germicides,  and  is  of  course  influenced  by  the  relative  mass 
of  bacteria  and  disinfectant,  as  well  as  by  temperature  and 
contact  between  the  reacting  substances.     The  instability 

1  Journ.,  Exp.  Med.,  23,  p.  601,  1916. 

2  B.  M.  J.,  May  13,  1916,  p.  684. 


84  A   HANDBOOK   OF  ANTISEPTICS 

of  many  antiseptics,  leading  to  a  reduction  or  disappearance 
of  the  mass  of  active  antiseptic,  must  also  be  reckoned  with. 
A  knowledge  of  the  speed  with  which  a  disinfectant  acts  is 
essential  to  an  understanding  of  the  conditions  under  which 
it  may  be  appropriately  used.  For  example,  the  extremely 
rapid  acting  aqueous  hypochlorites  are  admirably  adapted 
for  intermittent  instillation  in  large  quantities  into  wound 
cavities,  while  when  the  same  solutions  are  applied  as  wet 
dressings  which  are  seldom  renewed,  their  action  is  over  as 
soon  as  the  active  chlorine  has  disappeared,  and  this  may  be 
a  matter  of  only  seconds  or  minutes.  For  prolonged  action 
when  intermittent  instillation  cannot  be  practiced,  a  slower 
acting  but  more  stable  antiseptic  is  likely  to  give  better  re- 
sults, or  they  may  be  attained  by  using  an  oil  solution  of 
dichloramine-T  (p.  34)  from  which  the  active  antiseptic 
slowly  passes  from  the  oil  to  the  aqueous  medium  on  the 
surface  of  the  wound. 

The  only  satisfactory  way  to  follow  the  speed  of  disin- 
fection is  to  determine  the  progressive  change  in  the  number 
of  bacteria  in  a  suitable  mixture  after  varying  lengths  of 
time.  With  this  end  in  view,  we  have  made  a  number 
of  time  experiments  with  various  antiseptics,  using  them 
in  most  cases  at  about  the  concentration  which  is  recom- 
mended for  wound  treatment.  The  mixtures  contained  i 
cc.  of  horse  blood  serum,  i  cc.  of  muscle  extract  obtained 
by  soaking  fresh  veal  with  an  equal  weight  of  saline  and 
then  straining  through  cloth  but  not  filtering,  and  2  drops 
of  a  staphylococcus  aureus  emulsion  obtained  by  shaking  a 
24-hour  agar  slant  of  abundant  growth  with  8  cc.  of  saline. 
The  muscle  extract  doubtless  contained  organisms  of  other 
kinds  in  fair  quantity.  After  determining  the  total  number 
of  organisms  present  in  the  mixture  by  plating  an  aliquot 
part,  I  cc.  of  antiseptic  solution  was  added  and  samples  with- 
drawn from  time  to  time  and  the  surviving  bacteria  esti- 
mated.    In  the   case  of  chlorine   antiseptics,  their  further 


METHODS   OF    TESTING   ANTISEPTICS 


85 


action  after  sampling  was  checked  by  sodium  thiosulphate, 
while  potassium  sulphide  was  used  as  an  antidote  with  the 
salts  of  the  heavy  metals.  No  antidote  was  used  with  the 
dyes.  The  use  of  the  blood  serum-muscle  extract  medium 
was  chosen  as  bearing  some  similarity  to  the  composition  of 
wound  exudate  and  it  has  the  further  advantage  of  being 
easily  reproduced  in  fairly  uniform  quality.  For  many 
antiseptics,  the  addition  of  muscle  extract  makes  the  tests 
much  more  severe  than  when  blood  serum  alone  is  used. 
The  experiments  were  all  carried  out  at  32-35°  C.  and  the 
results  are  expressed  as  the  number  of  bacteria  present  in 
one  standard  drop  of  the  mixture  =  1/40  cc. 

I.  Chlorine  Group  of  Antiseptics 
(Blood  Serum-Muscle  Extract  Medium ;  Staphylococcus  aureus.) 


Antiseptic  Used 

Concentration 

Time  of 
Action 

Bacterial 

Count 

I  Drop=jVcc. 

As  Added 

In  Mixture 

I.   Sodium  Hypochlorite  . 

0.5% 

0.17% 

0 

2     min. 

5     min. 

I  966  000 

405 
oi 

II.  do.                  do.    .    . 

0.5% 
(0.2  cc.) 

0.05% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

I  966  000 

311  200 

157  400 

98  170 

16  120 

I  651 

1587 
I  294  000  2 

III.   Eusol 

0.27% 

0.09% 

0 

2     min. 

5     min. 

IS     min. 

2150  000 
496 
2 
0^ 

1  Active  chlorine  present. 


2  Active  chlorine  absent. 


86 


A   HANDBOOK   OF   ANTISEPTICS 


I,   Chlorine  Group  of  Antiseptics  —  Continued 
(Blood  Serum-Muscle  Extract  Medium ;  Staphylococcus  aureus.) 


Antiseptic  Used 

Concentration 

Time  of 
Action 

Bacterial 
Count 

I  DR0P  =  5\fCC. 

As  Added 

In  Mixture 

IV.   Eusol 

0.27% 
(0.2  cc.) 

0.025% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

2  129  000 

1  310  000 
507  900 
606  200 
641  400 
868  300 
983  000 

2  310  000  2 

V.   Chloramine-T     .     .     . 

2% 

0.67% 

0 

5     min. 

I  365  000 

VI.  do 

0.5% 

0.17% 

0 

5  min. 
IS     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 

726  300 

998 

•      191 

7 
4 
3 
o2 

VII.   Dichloramine-T  in  Oil 
(v,  p.  39) 

2% 

0.67%  3 

0 

0.5  min. 

2  020  000 
0 

VIII.  do 

2% 

0.67%  4 

0 

5     min. 
15     min. 
45     min. 

I  157  000 

458  700 

294  900 

0 

IX.   Iodine    in    Potassium 
Iodide , 

2% 

0.67% 

0 

5     min. 

I  463  000 
0 

The  results  shown  in  Table  I  in  which  members  of  the 
chlorine  group  of  antiseptics  and  iodine  are  considered,  il- 


1  Active  chlorine  present. 
3  Mixed  with  platinum  wire. 


2  Active  chlorine  absent. 
4  Not  mixed,  left  to  diffuse. 


METHODS   OF   TESTING   ANTISEPTICS 


87 


lustrate  their  extraordinary  speed  and  completeness  of  dis- 
infection when  added  in  adequate  amount  to  the  infected 
mixture.  In  Experiments  I,  III,  V,  VII,  and  IX,  -J  volume 
of  the  various  antiseptic  solutions  was  added  at  a  concen- 
tration no  higher  and  in  some  cases  lower  than  that  com- 
monly employed  in  wound  treatment  and  in  every  case 
practical  sterility  was  obtained  in  less  than  five  minutes. 
When  much  smaller  amounts  of  hypochlorites  were  added, 
as  in  Experiments  II  and  IV,  their  rapid  action  is  seen  to 
cease  as  soon  as  all  the  active  antiseptic  is  decomposed  and 
subsequent  growth  can  then  take  place.  In  Experiment 
VI,  in  which  weak  (0.5  per  cent)  chloramine-T  was  used,  its 
action  is  shown  to  be  distinctly  more  effective  than  an  ap- 
proximately equivalent  amount  of  chlorine  in  the  form  of 
sodium  hypochlorite  or  hypochlorous  acid  (Experiments  II 
and  IV). 

II.  Metallic  Salts,  Phenol,  Hydrogen  Peroxide 
(Blood  Serum-Muscle  Extract  Medium ;  Staphylococcus  aiureus.) 


Antiseptic  Used 

Concentration 

Time  of 
Action 

Bacterial 

Count 

I  Drop— 50  CO. 

As  Added 

In  Mixture 

I.   Mercuric  Chloride  .     . 

0.1% 

0.033% 

0 

5     min. 
15     min. 
45     min. 

1.5  hr. 

3     hr. 
24     hr. 

I  894  000 

254  400 

44920 

12  900 

7258 

2985 

0 

II.   Silver  Nitrate     .     .     . 

1% 

0.33% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

786  400 
720  900 
651  700 
530  600 
425  900 
17s  600 
38270 
2  643 

A   HANDBOOK   OF   ANTISEPTICS 


II.  Metallic  Salts,  Phenol,  Hydrogen  Ve^oxide  —  Continued 
(Blood  Serum-Muscle  Extract  Medium;  Staphylococcus  aureus.) 


Antiseptic  Used 

Concentration 

Time  of 
Action 

Bacterial 

Count 

I  Drop=jVcc. 

As  Added    !  Jn  Mixture 

III.  Argyrol 

15% 

5% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

917  500 

753  500 

655  300 

622  500 

327  600 

9792 

4693 

0 

rV.   Zinc  Chloride     .     .     . 

3% 

1% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

I  223  000 

868  300 

819  200 

491  500 

211  900 

51  580 

3667 

704 

V.   Hydrogen  Peroxide 

2.89% 

0.96% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 

I  201  000 
589  800 
819  200 
778  200 
802  800 
I  087  000 
I  136  000 

VT.   Phenol 

2% 

0.67% 

0 

5     min. 
15     min. 
45     min. 

1.5  hr. 

3     hr. 
24     hr. 

I  409  000 

I  471  000 

819  200 

192  700 

34900 

13  700 

2985 

In  the  second  series  of  experiments  a  similar  infected 
medium  of  blood  serum  and  muscle  extract  was  mixed  with 
solutions  of  various  metallic  salts,  phenol,  and  hydrogen 


METHODS   OF    TESTING   ANTISEPTICS 


89 


peroxide.  Mercuric  and  zinc  chlorides  and  silver  nitrate 
produced  immediate  precipitates.  The  action  of  mercuric 
chloride  o.i  per  cent  is  seen  to  be  more  rapid  than  that  of 
phenol  2  per  cent,  silver  nitrate  i  per  cent,  or  zinc  chloride  3 
per  cent.  Argyrol  was  tried  in  very  high  concentration  and 
while  acting  slowly  sterilized  completely  in  24  hours.  Neither 
phenolj  silver  nitrate,  nor  zinc  chloride  sterilized  completely 
in  24  hours,  although  the  number  of  viable  organisms  was 
less  than  i  per  cent  of  those  originally  present  in  the  mix- 
ture. The  effect  of  hydrogen  peroxide  is  interesting  as 
showing  an  extremely  rapid  but  transitory  action  which 
reached  its  maximum  in  a  few  minutes,  after  which  the 
organisms  grew  unchecked. 

III.  Dyes 
(Blood  Serum-Muscle  Extract  Medium ;  Staphylococcus  aureus.) 


Concentration 

Time  of 
Action 

Bacterial 

Antiseptic  Used 

Count 
I  Drop =5^0  CO. 

As  Added 

In  Mixture 

I.   Malachite  Green  .     . 

0.3% 

0.1% 

0 

821  600 

(Grubler) 

5  mm. 
15     min. 

1.5  hr. 
'•  3     hr. 

6  hr. 
24     hr. 
48     hr. 

182  700 

60  920 

8  920 

5  574 

78  200 

I  015  000 

3  706  000 

II.  do.     .     .      do.  .     .     . 

0.1% 

0.033% 

0 

5  min. 
15     min. 
45     min. 

3     hr. 

6  hr. 
24     hr. 
48     hr. 

2  097  coo 
I  359  000 

369  TOO 

211  500 

272  300 

557  000 

I  096  000 

6  553  000 

90 


A    HANDBOOK  OF   ANTISEPTICS 


III.    Dyes  —  Continued 
(Blood  Serum-Muscle  Extract  Medium;  Staphylococcus  aureus.) 


Antiseptic  Used 

Concentration 

Time  of 

Bacterial 
Count 

As  Added 

In  Mixture 

I  Drop =5^5  CO. 

III.   Brilhant  Green  .     .     . 

0.3% 

0.1% 

0 

810  200 

(Griibler) 

5  mm. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

29    9SO 

27  410 

20  160 

14  310 

8871 

I  946 

256  600 

48     hr. 

658  900 

IV.  Acriflavine     .... 

0.3% 

0.1% 

0 

5  min. 
15     min. 
45     min. 

1. 5  hr. 

6  hr. 
24     hr. 

589  800 

358  400 

249  300 

179  200 

78  210 

704 

0 

V.   do 

0.1% 

0.033% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 

6  hr. 
24     hr. 

557  100 
218  600 
121  900 
100  800 
81  540 

474 
0 

VI.   do 

0.03% 

0.01% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

755  400 

524  300 

319  300 

308  200 

106  500 

94  840 

22  780 

I  113  000 

Vn.   Proflavine 

0.3% 

0.1% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 

888  100 
794  500 
744  500 
308  200 
104  800 
66  560 
53  250 

1 

24     hr. 

I  242 

METHODS   OF    TESTING   ANTISEPTICS 


91 


III.   Dyes  —  Continued 
(Blood  Serum-Muscle  Extract  Medium  ;  Staphylococcus  aureus.) 


Concentration 

I 

Antiseptic  Used 

Time  of 
Action 

Bacterial 

Count 

I  Drop=J5cc. 

As  Added 

In  Mixture 

VIII.    Proflavine       .... 

o.i% 

0.033% 

0 

5  min. 
15     min. 
45     min. 

1.5  to:. 
3     hr. 

6  hr. 
24     hr. 

888  100 
744  500 
655  400 
326  100 
169  900 
154  800 
84  900 
4 

IX.   do.    . 

0.03% 

0.01% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

855  400 
761  800 
744500 
469  500 
304  500 
196  400 
93  750 
183  600 

In  the  third  series  of  experiments  the  action  of  malachite 
green,  brilliant  green,  and  acriflavine  acting  in  a  similar  mix- 
ture of  blood  serum  and  muscle  extract  were  examined.  The 
germicidal  action  of  these  dyes,  in  view  of  claims  made  for 
them,  proved  disappointing.  Brilliant  green  has  been  recom- 
mended for  use  by  Browning  and  his  colleagues  at  a  concen- 
tration of  0.1  per  cent  but  addition  of  one  third  volume  of 
brilJiant  green  or  malachite  green  at  this  concentration  gave 
but  poor  evidence  of  much  germicidal  action.  Subsequent 
experiments  with  these  two  dyes  were  made  at  a  higher 
concentration,  0.3  per  cent.  In  no  case  was  sterility 
reached  and  after  some  hours  the  organisms  grew  unchecked. 
It  was  noted  that  similar  mixtures  of  blood  serum  and  muscle 


92  A    HANDBOOK   OF   ANTISEPTICS 

extract  mixed  with  these  dyes  so  that  the  final  concentration 
was  O.I  per  cent,  on  exposure  to  air  readily  underwent 
thorough  putrefaction.  It  would  appear  that  under  the  con- 
ditions of  these  experiments  the  dyes  in  question  are  readily 
inactivated  and  that  the  presence  of  apparently  unchanged 
coloring  matter  in  the  mixture  is  no  evidence  of  the  continua- 
tion of  any  antiseptic  action.  Similar  experiments  with 
acriflavine,  o.i  per  cent,  showed  a  slow  initial  effect  but  anti- 
septic action  was  more  sustained,  and  while  sterility  was  not 
attained  in  six  hours,  after  24  hours  disinfection  was  com- 
plete. When  the  concentration  of  the  acriflavine  solution 
added  was  0.03  per  cent  more  organisms  were  present  at  the 
end  of  24  hours  than  at  the  commencement  of  the  experi- 
ment. The  results  with  proflavine  were  not  widely  different 
from  acriflavine,  although  the  higher  concentrations  did 
not  effect  perfect  sterihzation  in  24  hours.  The  effect  of 
these  dyes  appears  more  pronounced  when  acting  in  blood 
or  blood  serum  than  when  muscle  extract  is  present. 

We  have  also  made  some  experiments  in  the  progressive 
change  in  the  bacterial  count  when  various  chlorine  antiseptics 
and  dyes  were  added  to  defibrinated  blood.  With  the  excep- 
tion of  the  sodium  hypochlorite  and  eusol  tests  these  experi- 
ments were  made  by  adding  one  volume  of  antiseptic  to  two 
volumes  of  freshly  drawn  sterile  rabbit  blood  heavily  inocu- 
lated with  staphylococcus  aureus.  The  general  conditions  of 
the  experiments  were  identical  with  those  preceding. 


METHODS   OF    TESTING   ANTISEPTICS 


93 


IV.   Chlorine  Group  of  Antiseptics 
(Defibrinated  Blood  Medium ;  Staphylococcus  aureus.) 


Antiseptic  Used 

Concentration 

Time  of 
Action 

Bacterial 

Count 

I  Drop=5Vcc. 

As  Added 

In  Mixture 

I.   Sodium  Hypochlorite  . 

0.5% 

0.33% 

0 

5  min. 
15  min. 
45  min. 

573  400 

563 

282 

2432 

II.   do.         do 

0.5% 

0.3% 

0 

5  min. 
15  min. 
45  min. 

573  400 

I  774 

1485 

19656 

III.   do.         do 

0.5% 

0.25% 

0 
45  min. 

232  900 
89  600 

IV.   Eusol 

0.27% 

0.18% 

0 

5  min. 
15  min. 
45  min. 

578  600 

I  562 

2330 

36  600 

V.   do 

0.27% 

0.16% 

0 

5  min. 
15  jnin. 
45  min. 

811  000 
36  280 
48  250 
51  580 

VI.  do 

0.27% 

0.13% 

0 

5  min. 

260  800 
143  300 

^11.   Chloramine-T     .     .     . 

2% 

0.67% 

0 

5  min. 
15  min. 

224  500 

125 

0 

VII.   do 

1% 

0.5% 

0 
45  min. 

235  600 
0 

VIII.   do 

0.75% 

0.25% 

0 

5  min. 
15  min. 
45  min. 

3  hr. 

I  178  000 
20  160 

5  451 

4032 

806 

IX.    Dichloramine-T  in  Oil 

2% 

0.67%  1 

0 

2  min. 

59900 
0 

Mixture  stirred  with  platinum  wire. 


94  A   HANDBOOK  OF  ANTISEPTICS 

The  results  of  the  action  of  0.5  per  cent  sodium  hypochlorite 
and  of  eusol  on  staphylococci  in  a  blood  medium  show  that  a 
relatively  large  addition  of  these  must  be  made  before  any 
marked  germicidal  effect  is  produced.  Even  when  two 
volumes  of  the  antiseptic  were  added  to  one  of  infected  blood, 
complete  sterilization  was  not  quite  accomplished,  although 
considerably  over  99  per  cent  of  the  organisms  were 
killed.  As  already  stated,  the  reason  for  the  apparent 
low  germicidal  action  of  hypochlorites  in  a  blood  medium  is 
due  to  their  ready  decomposition  by  the  haemoglobin  and 
other  substances  in  the  blood.  From  a  practical  standpoint 
this  is  not  of  much  importance  when  methods  of  intermittent 
instillation  of  hypochlorite  solution  into  wounds  are  practiced 
but  it  serves  to  emphasize  the  necessity  for  the  frequent 
renewal  of  the  solution. 

Chloramine-T  and  dichloramine-T  give  materially  better 
results  than  the  hypochlorites  when  acting  on  organisms 
in  a  blood  medium.  A  comparison  of  Experiments  I  and  IX 
shows  that  a  concentration  of  0.25  per  cent  of  chloramine-T 
in  the  mixture  was  as  effective  as  0.33  per  cent  sodium  hy- 
pochlorite, although  the  active  chlorine  in  the  latter  was 
about  five  times  as  much  as  that  in  the  chloramine-T.  The 
reason  for  this  difference  is  to  be  sought  largely  in  the  slower 
rate  of  reaction  between  chloramine-T  and  haemoglobin  and 
other  proteins,  compared  with  the  hypochlorite  solutions. 


METHODS   OF   TESTING   ANTISEPTICS 


96 


V.  Dyes 

(Defibrinated  Blood  Medium ;  Staphylococcus  aureus.) 


Antiseptic  Used 

Concentration 

Time  of 
Action 

Bacterial 

Count 

iDrop=4%cc. 

As  Added 

In  Mixture 

I.  Malachite  Green     .     . 
(Griibler) 

0.3% 

0.1% 

0 

5  min. 
15     min. 
45     min, 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 
72     hr. 

I  754  000 

107 

88 

66 

82 

35 

36 

13 

0 

II.  do 

0.1% 

0.033% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr, 

6  hr. 
24     hr. 

I  693  000 

I  310  oco 

819  200 

208  000 

146  900 

86010 

89  600 

I  219  000 

III.   BriUiant  Green  .     .     . 
(Griibler) 

0.3% 

0.1% 

0 

5     min. 

I  966  000 
0 

IV.   do.        do 

0.1% 

0.033% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

I  630  000 

1  261 

563 

755 
717 

857 

2  592 
I  171  000 

V.  Acriflavine     .... 

0.3% 

0.1% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

654  600 

358  400 

108  800 

98  180 

I  472 

203 

17 

0 

96 


A  HANDBOOK  OF  ANTISEPTICS 


V.  Dyes  —  Continued 
(Defibrinated  Blood  Medium ;  Staphylococcus  aureus.) 


Antiseptic  Used 

Concentration 

Time  of 
Action 

Bacterial 

Count 

iDrop=5\cc. 

As  Added 

In  Mixture 

VI.   Acriflavine     .... 

o.i% 

0.03% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

654  700 

411  goo 

225  800 

138  100 

30  640 

I  152 

32 

0 

VII.   do.    . 

0.03% 

0.01% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

goo  600 

819  200 

508  900 

igo  000 

83  860 

32  260 

768 

3 

Vni.   Proflavine       .... 

0.3% 

0.1% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

819  200 

4710 

1638 

474 

304 

113 

12 

0 

IX.   do 

0.1% 

0.033% 

0 

5  min. 
15     min. 
45     min. 

1.5  hr. 
3     hr. 

6  hr. 
24     hr. 

819  200 
201  300 
208  000 
122  500 
53  220 
29  670 

2  9g5 

2 

X.  do 

0.03% 

0.01% 

0 

5  min. 
15     min. 
45     min. 

1-5  hr. 
3     hr. 

6  hr. 
24     hr. 

8ig  200 
753  700 
852  000 
5QI  400 
394  200 
448  000 
48380 
282 

METHODS  OF   TESTING  ANTISEPTICS  97 

The  "  action  of  malachite  green  and  brilliant  green  in 
bloo.d  heavily  infected  with  staphylococcus  aureus  was  dis- 
appointing. In  only  one  case,  namely  with  brilliant  green, 
did  a  concentration  of  o.i  per  cent  in  the  mixture  bring  about 
apparent  sterility.  It  is  by  no  means  certain  that  even  in 
this  case  all  the  organisms  were  killed,  since  it  was  not  pos- 
sible to  avoid  carrying  over  of  some  of  the  dye  to  the  agar 
subcultures,  and  in  the  concentration  referred  to  we  showed 
that  reproduction  of  living  staphylococci  actually  was  in- 
hibited, although  they  were  not  killed.  It  is  significant  that 
wdth  the  exception  of  the  two  experiments  in  which  brilliant 
green  and  malachite  green  were  added  in  0.33  per  cent  solu- 
tion, an  initial  fall  in  the  number  of  bacteria  was  followed 
by  practically  unrestricted  growth.  These  results  are  in 
marked  contrast  to  those  of  Browning  and  his  colleagues 
referred  to  in  Chapter  V.  The  action  of  acriflavine  and 
proflavine  in  blood,  while  slow,  is  seen  to  be  distinctly 
superior  to  that  of  the  other  dyes. 

In  judging  of  the  suitability  of  substances  for  wound 
treatment,  there  are  of  course  other  factors  to  be  considered " 
besides  germicidal  efficiency.  Prominent  among  these  is 
the  determination  of  the  concentration  at  which  irritation 
of  the  skin  and  other  tissues  becomes  noticeable,  also  the 
effect  of  germicidal  substances  upon  phagocytosis  and  their 
influence  if  any  on  the  rate  of  dissolution  of  necrotic  tissue. 
All  of  these  factors  may  best  be  investigated  in  vivo.  Ref- 
erence may  be  made  to  Colonel  Bond's  ingenious  experiments 
noted  on  p.  11  with  regard  to  phagocytic  activity  as  influenced 
by  antiseptics. 

Laboratory  experiments  serve  primarily  for  the  sorting 
out  of  substances  which  are  likely  to  be  of  value  for  wound 
antisepsis,  and  they  are  particularly  important  in  indicating 
the  mode  of  use  for  the  selected  substance  which  is  most 
likely  to  give  successful  clinical  results,  but  the  final  decision 
of  the  utility  of  any  germicide  will  necessarily  follow  from  a 


98  A   HANDBOOK   OF   ANTISEPTICS 

study  of  its  effects  upon  actual  wounds.  The  treatment  of 
comparable  infected  wounds  with  various  antiseptics,  accom- 
panied by  daily  bacteriological  estimations  of  the  degree  of 
infection  gives  most  useful  results.  This  method  has  been 
practiced  extensively  in  the  present  war  and  gives  valuable 
indications  as  to  the  earliest  date  at  which  wounds  may  be 
safely  closed  by  suture  or  otherwise.  The  influence  of 
antiseptics  on  the  rate  of  cicatrization  of  wounds  may  also 
be  followed  with  the  aid  of  a  formula  worked  out  by  Du 
Noiiy.^  The  technique  of  these  experimental  methods  is 
beyond  the  scope  of  this  book  and  reference  should  be  made 
to  original  sources. 

1  Journ.,  Exper.  Med.,  24,  pp.  451,  461,  1916;  25,  p.  721,  1917. 


CHAPTER  VIII 

CERTAIN   SPECIAL   APPLICATIONS   OF   ANTISEPTICS 

I.   The  Disinfection  of  Carriers 

The  problem  of  destroying  pathogenic  organisms  in  the 
nasal  and  upper  air  passages  by  direct  disinfection  is  a  difi&- 
cult  one.  There  are,  undoubtedly,  many  carriers  with 
anatomical  abnormalities  of  the  nose,  pharyngeal  vault  and 
tonsils  precluding  immediate  contact  with  solutions  used 
either  as  sprays  or  gargles.  In  such  cases  there  is  little  pros- 
pect of  any  antiseptic  proving  effective.  Those  organisms 
which  are  exposed  to  direct  contact  with  the  antiseptic 
solution,  may  be  destroyed,  but  in  the  course  of  time  those 
which  have  preserved  their  vitality  in  protected  situations 
regenerate  the  original  condition  and  only  a  temporary, 
although  to  that  extent  beneficial,  result  is  attained.  This 
difficulty  is  encountered  in  chronic  diphtheria  carriers,  in 
whom  deep  tonsilar  crypts  are  frequently  encountered  form- 
ing inaccessible  regions  in  which  the  bacilli  are  afforded  pro- 
tection. The  pneumococcus,  existing  in  the  pulmonary  air 
passages,  is,  in  those  parts,  wholly  beyond  reach.  In  con- 
sidering the  applicability  of  treatment  to  individual  cases, 
these  inevitable  limitations  must  be  taken  into  account. 

In  spite  of  these  limitations,  chiefly  imposed  by  anatomical 
conditions,  valuable  results  have  been  obtained,  notably 
by  Gordon  and  Flack,  with  the  use  of  antiseptics  in  the 
treatment  of  meningococcus  carriers  among  soldiers.  By 
a  suitable  choice  of  antiseptic,  properly  applied,  there  is  no 
doubt  that  much  can  be  accomplished  in  limiting  the  risks 

9U 


100  A   HANDBOOK   OF   ANTISEPTICS 

connected  with  carriers  of  pathogenic  organisms,  both   to 
themselves  and  those  coming  in  contact  with  them. 

The  methods  that  have  been  employed  with  most  success 
are  the  following : 

(i)  Chamber  disinfection  using  a  steam  spray  and  a 
solution  of  chloramine-T  or  zinc  sulphate  (Gordon  and 
Flack).  Hypochlorites  have  also  been  used  for  chamber 
disinfection,  but  they  have  not  been  found  as  satisfactory.^ 

(2)  Local  application  of  various  antiseptics  including 
iodine,  with  either  micnthol,  guaiacol  or  glycerine,  argyrol 
and  hydrogen  peroxide,  zinc  salts,  acriflavine,  chloramine-T 
and  especially  dichloramine-T  in  oil  solution.  Ferric  chloride 
and  potassium  permanganate  solutions  have  given  only  mod- 
erate results  while  formalin  appears  to  be  distinctly  harmful. 

Gordon  and  Flack  found  that  many  of  the  antiseptic 
solutions  employed  as  gargles  and  in  hand  sprays  at  the 
time  when  they  commenced  their  experiments  gave  un- 
satisfactory results  when  used  on  heavily  infected  chronic 
carriers.  This  appeared  to  be  due  as  much  to  lack  of  per- 
fect contact  as  to  germicidal  inefficiency.  They  therefore 
employed  an  inhalation  chamber  with  a  steam  pressure 
spray  or  atomizer  capable  of  converting  the  antiseptic 
solution  into  a  fine  mist.  The  chamber  was  about  750  to 
1000  cubic  feet  capacity,  and  the  apparatus  was  capable  of 
spraying  a  liter  of  antiseptic  solution  in  the  course  of  twenty 
minutes.  A  working  diagram  of  two  forms  of  these  sprays 
will  be  found  in  Gordon  and  Flack's  original  paper ,2  in  which 
there  will  also  be  found  details  of  the  successful  treatment  of 
numbers  of  chronic  meningococcus  carriers.  The  prepared 
antiseptic  solution  used  for  spraying  by  Gordon  and 
Flack  was  either  chloramine-T,  0.5  per  cent,  or  zinc  sulphate, 
1.2  per  cent.  The  chloramine-T  gave  the  better  results, 
especially  with  persistent  carriers,  but  is  somewhat  less  well 

1  Kuster,  Deutsch.  Med.  Woch,  41,  p.  11 16,  1915. 

2  Brit.  Med.  Journ.,  p.  673,  Nov.  18,  1916. 


THE   DISINFECTION  OF   CARRIERS 


101 


tolerated  than  the  zinc  salt.  The  inhalation  was  carried 
out  once  daily  and  on  each  occasion  the  carriers  were  in  the 
inhaling  room  from  fifteen  to  twenty  minutes  during  which 
time  they  vigorously  inhaled  the  spray-laden  atmosphere 
through  the  nostrils. 

Using  a  different  apparatus  with  a  high  pressure  air  spray, 
the  authors  ^  have  examined  the  antiseptic  action  of  chlor- 
amine-T  solution  on  the  mJxed  bacterial  flora  of  the  normal 
nasopharynx.  The  results  are  recorded  in  the  following 
table  in  which,  for  comparison,  the  effect  of  spraying  with 
salt  solution  is  included.  The  figures,  which  are  the  aver- 
age of  six  similar  experiments,  indicate  the  total  number  of 
organisms  obtained  from  plating  a  swab  taken  under  approxi- 
mately constant  conditions  and  in  which  any  antiseptic 
adhering  to  the  swab  was  immediately  destroyed  with 
sterile  sodium  thiosulphate  solution. 

Aqueous  Chloramine-T  and  Neutral  Salt  Solution 


Number  of  Colonies  Derived  from  Sample 

First  Period 

Second  Period 

Time  of  Treatment 

5  min. 

10  min. 

IS  min. 

5  min. 

ID  min. 

IS  min. 

0.5%  chloramine-T 
(control,  43.240) 

Normal  salt  solution 
(control,  56.738) 

1,331 
12,352 

707 
121,620 

526 
13,587 

439 
2,137 

153 
10,055 

17 
34,339 

From  these  and  other  results,  it  appeared  that  exposure 
to  the  chloramine-T  spray  for  less  than  fifteen  minutes  was 
not  very  effective  and  that  frequent  repetition  of  the  treat- 
ment was  desirable.     Repetition  several  times  daily  of  the 

1  Brit.  Med.  Journ.,  June  23,  1917. 


102 


A   HANDBOOK   OF   ANTISEPTICS 


chloramine-T  spray  for  15  or  20  minute  periods  is  rather  a 
severe  procedure,  so  that  as  an  alternative  we  have  em- 
ployed an  oily  solution  of  the  related  dichloramine-T  (see 
p.  33),  which  has  the  great  advantage  that  its  action  is  much 
more  prolonged,  owing  to  the  slow  diffusion  of  the  antisep- 
tic into  the  aqueous  nasal  secretions.  The  oil  solution  is 
sprayed  into  the  nose  and  throat  from  an  ordinary  oil  spray, 
preferably  one  made  entirely  of  glass,  thus  avoiding  the 
necessity  of  an  inhalation  chamber. 


Appli- 

cations 

Time  of  Test, 

Number  of 

Treatment  Employed 

OF  Oil 

FROM  Beginning 

Colonies  on 

between 

OF  Treatment 

Agar  Plate 

Tests 

I. 

0.5%     aq.     chloramine-T 

0 

0 

42,240 

followed  by  2%  di-chlor- 

I 

30  min. 

9 

amine-T  in  oil. 

0 

60  min. 

0 

II. 

1.5%    dichloramine-T   in 

0 

0 

16,104 

oil. 

I 

I  hour 

175 

I 

3.5  hours 

I 

0 

6  hours 

9 

III. 

0.5%    aq.     chloramine-T 

0 

0 

6,129 

followed    by    1.3%   di- 

I 

I  hour 

8,960 

chloramine-T  in  oil. 

4 

4  hours 

87 

0 

20  hours 

1,980     . 

I 

22  hours 

59 

I 

24  hours 

3 

I 

26  hours 

I 

I 

27.5  hours 

20 

Experience  in  the  treatment  of  meningococcus  carriers 
with  2  per  cent  dichloramine-T  dissolved  in  chlorinated 
eucalyptol  and  paraffin  (1:4)  has  as  yet  been  limited,  but 
many  cases  treated  have  been  promptly  freed  from  the  me- 
ningococcus and  the  method  appears  likely  to  be  used  ex- 
tensively. The  above  table  shows  the  effect  of  spraying 
the  oil  solution  of  dichloramine-T  on  the  normal  nose.  In 
such  experiments  it  must  be  recalled  that  many  of  the  bac- 


THE   DISINFECTION   OF   CARRIERS  103 

teria  are  much  more  resistant  to  antiseptics  than  the  menin- 
gococcus and  that  spore  forms  were  probably  present. 

In  the  above  experiments,  the  strongest  solution  was  2 
per  cent  and  the  result  was  very  striking.  It  should  be 
understood,  however,  that  the  concentration  of  the  antisep- 
tic in  the  oil  bears  no  simple  relation  to  the  strength  ac- 
tually applied  to  the  organisms  in  the  aqueous  secretions. 
For  example,  a  sample  of  the  oil  containing  2  per  cent  di- 
chloramine-T,  when  shaken  with  an  equal  volume  of  clear 
nasal  secretion,  showed  that  the  filtered  aqueous  portion 
had  a  concentration  of  active  chlorine  corresponding  to  about 
0.1  per  cent  dichloramine-T.  The  chief  advantage  of  using  a 
concentrated  oil  solution  lies  in  prolonging  the  period  through 
which  it  can  serve  as  a  store  of  active  antiseptic.  In  the 
normal  nose,  a  2  per  cent  solution  is  not  exhausted  until 
about  two  hours  have  elapsed;  but  when  foul  discharges 
are  present,  this  period  would  be  curtailed. 

The  experience  hitherto  gained  in  the  treatment  of  carriers 
with  dichloramine-T  indicates  that  the  following  procedure 
may  be  advantageously  followed : 

First  cleanse  the  nose  with  normal  salt  solution,  with  or 
without  the  addition  of  0.25  per  cent  chloramine-T,  by  spray- 
ing, or  irrigation.  The  same  chloramine-T  solution  should 
be  used  as  a  gargle.  After  this  preliminary  treatment  and 
when  the  augmentation  of  nasal  secretion  has  subsided, 
apply  the  oil  solution  of  dichloramine-T  ^  (2  per  cent)  with 
an  oil  "atomizer,"  endeavoring  to  reach  all  the  parts  with 
an  abundant  supply  of  oil.  It  is  not  certain  that  the  oil  so 
introduced  is  ever  active  for  more  than  two  hours,  so  that 
for  intensive  treatment  it  should  be  renewed  at  the  end  of 

1  This  solution  is  best  prepared  by  dissolving  0.2  gram  of  dichloramine-T 
in  10  cc.  chlorcosane  rendered  more  fluid,  if  need  be,  with  i  cc.  carbon  tetra- 
chloride. The  solution  should  be  discarded  as  soon  as  signs  of  a  considerable 
crystalline  sediment  appear.  Ordinarily  it  is  stable  for  several  weeks.  It 
should  be  carefully  protected  as  far  as  possible  from  direct  exposure  to  sunlight, 
as  this  hastens  its  decomposition. 


104  A   HANDBOOK   OF   ANTISEPTICS 

that  time.  In  any  case,  it  appears  important  to  repeat 
spraying  with  the  oil  so  that  four  treatments  a  day  are 
given  at  about  equal  intervals.  The  first  few  applications 
of  oil  sometimes  occasion  sneezing,  but  the  nose  appears  to 
acquire  a  tolerance  for  the  treatment,  and  subsequent  applica- 
tions occasion  no  inconvenience.  In  cases  of  acute  coryza, 
dichloramine-T  applied  as  described  is  too  irritating  to  the 
inflamed  membrane  and  its  use  is  not  advised. 

In  the  way  of  prophylaxis,  spraying  of  the  upper  air  pas- 
sages with  a  0.25  per  cent  solution  of  chloramine-T  in  saline, 
or  an  oil  solution  of  dichloramine-T  appears  to  be  followed 
by  good  results  in  reducing  the  incidence  of  coryza,  measles 
and  mumps,  although  it  is  not  possible  to  cite  convincing 
statistical  evidence.  Colonel  Parke's  ^  report  on  army  trans- 
ports covering  long  voyages  in  which  an  inhalatorium  of  the 
Gordon  and  Flack  type  was  used,  lends  support  to  the  view 
that  such  treatment  is  useful.  The  simplicity  of  these 
methods  and  the  apparent  value  of  the  results  indicate  that 
more  extended  trials  are  desirable. 

Among  the  other  antiseptic  solutions  employed  in  the 
treatment  of  meningococcus  carriers,  reference  may  be  made 
to  an  iodine  and  menthol  preparation  frequently  employed 
in  England,  while  Vincent  in  the  French  army  advocated 
the  following  mixture  as  an  inhalation:  iodine  12  grams, 
potassium  iodide '6  grams,  guaiacol  2  grams,  thymol  0.35 
gram,  alcohol  200  grams,  used  five  or  six  times  a  day.  For 
disinfection  of  the  pharynx,  swabbing  with  a  3  to  5  per  cent 
solution  of  glycerine  and  iodine  is  advocated.  This  would 
appear  a  decidedly  drastic  treatment.  Sophian  has  recom- 
mended hydrogen  peroxide  i  per  cent  and  argyrol  9  per 
cent,  used  as  a  spray,  as  of  value  for  freeing  carriers  of  me- 
ningococci, although  the  mixture  does  not  seem  to  have  been 
used  extensively  in  military  centres. 

The  antiseptic  treatment  of  carriers  has  been  much  more 

1  Brit.  Med.  Journ.,  Feb.  24,  1917. 


THE   DISINFECTION   OF   WATER  105 

successful  in  meningococcus  cases  than  with  most  other  infec- 
tions. The  reasons  for  this  are  doubtless  due  in  large  meas- 
ure to  the  fact  that  the  meningococcus  is  very  readily  killed 
by  antiseptics  and  is  usually  found  in  situations  accessible 
to  treatment.  The  treatment  of  diphtheria  carriers  has  been 
less  successful,  though  encouraging,  while  pneumococcus 
carriers  give  disappointing  results.  The  reasons  for  this 
are  obvious  when  the  pathological  conditions  are  considered. 

II.   The  Disinfection  of  Water 

The  chemical  disinfection  on  a  large  scale  of  contaminated 
or  suspected  water  supplies  for  civilian  military  or  naval 
use  is  now  almost  exclusively  effected  with  substances 
belonging  to  the  chlorine  group. ^  When  working  with 
considerable  volumes  of  water,  the  choice  of  reagent  is  prac- 
tically limited  to  free  chlorine  supplied  from  cylinders  of 
the  liquefied  gas,  sodium  hypochlorite  solutions  of  known 
concentration,  or  bleaching  powder  (chloride  of  lime).  The 
action  of  these  substances  is  essentially  similar,  and  their 
usefulness  depends  upon  the  fact  that  their  addition  in  such 
quantity  that  about  0.5  to  i  part  of  active  chlorine  per 
million  parts  of  water  persists  for  a  short  period,  is  followed 
by  an  almost  complete  disappearance  of  organisms  of  the 
coli  group.  Spore  forms  which  are  of  little  hygienic  impor- 
tance are  not  much  affected.  Preliminary  filtration  of 
turbid  waters  is  desirable,  and  occasionally  in  the  case  of 
extreme  turbid  waters,  clarifying  with  some  precipitant, 
such  as  alum  followed  by  alkali,  is  resorted  to. 

The  choice  of  reagent  will  depend  largely  upon  the  actual 
conditions  of  its  employment.  When  large  volumes  of 
water  are  to  be  treated  and  liquefied  chlorine  is  available, 

1  An  old  chemical  method  of  purifying  water  depended  on  the  use  of  potassium 
permanganate.  Except  against  the  cholera  spirillum,  it  is  not  very  effective, 
and  the  cost  of  the  material,  and  the  disagreeable  appearance  and  taste  of  the 
treated  water,  are  serious  drawbacks. 


106  A   HANDBOOK   OF  ANTISEPTICS 

this  may  be  the  most  convenient  method,  and  especially 
if  a  gas  gauge  such  as  the  Wallace-Tiernan  is  employed 
by  means  of  which  the  desired  chlorine  concentration  in  a 
known  quantity  of  water  may  be  easily  regulated.  Sodium 
hypochlorite  solution  is  preferable  to  bleaching  powder  in 
that  it  is  more  readily  distributed  through  the  water,  but 
its  varying  composition  and  instability  make  it  less  satis- 
factory for  field  use.  For  the  sterilization  of  moderate 
volumes  of  water  such  as  those  contained  in  army  water 
carts,  e.g.  no  gallons,  bleaching  powder  has  given  most 
satisfactory  results. 

The  successful  use  of  chlorine  compounds  for  the  disin- 
fection of  water  depends  largely  upon  adequate  mixing 
with  the  water;  the  use  of  an  effective  concentration  of 
disinfectant  such  as  that  already  indicated ;  and  lastly  the 
avoidance  of  excess.  The  taste  and  smell  of  unnecessarily 
highly  chlorinated  water  is  objectionable  to  most  people. 
Not  infrequently  a  reducing  substance  such  as  sodium 
thiosulphate  is  added  to  remove  the  excess  of  chlorine,  but 
with  careful  chlorination  this  should  not  be  necessary.  The 
exact  amount  of  disinfectant  to  be  added  to  water  can  only 
be  fixed  with  regard  to  individual  supplies  of  constant  com- 
position. The  reason  for  this  is  that  different  waters  con- 
tain such  varying  amounts  of  organic  matter  and  some- 
times ferrous  salts  or  sulphides  as  well,  and  the  chlorine 
used  up  in  oxidizing  these  substances  will  not  effect  steriliza- 
tion. A  slight  excess  only  of  the  disinfectant  must  therefore 
be  employed,  and  the  proper  amount  is  most  readily  deter- 
mined by  adding  a  little  more  (e.g.  0.5  to  i  per  million)  than 
the  minimum  quantity  necessary  for  obtaining  a  positive 
reaction  for  active  chlorine  in  the  water.  The  test  for  active 
chlorine  is  most  easily  carried  out  by  adding  a  few  drops  each 
of  10  per  cent  potassium  iodide  solution  and  starch  paste  to 
about  200  cc.  of  water  and  noting  whether  a  blue  color  de- 
velops.    Since  starch  paste  is  apt  to  become  mouldy,  it  is 


THE  DISINFECTION   OF   WATER  107 

often  convenient  to  use  zinc  iodide  (7.5  per  cent)  in  place  of 
the  potassium  salt  and  to  add  this  directly  to  the  starch 
paste  together  with  two  per  cent  of  alcohol.  This  mix- 
ture keeps  well.  Various  simple  devices  have  been  used 
for  carrying  out  this  test  in  the  field  so  that  accurate  dosage 
may  be  rapidly  determined.  It  should  be  remembered 
that  the  sensitiveness  of  the  starch-iodide  reaction  for  active 
chlorine  rapidly  diminishes  with  rise  in  temperature  of  the 
water.  The  speed  with  which  the  reaction  for  active  chlorine 
disappears  from  a  treated  water  depends  upon  many  factors, 
such  as  the  degree  of  surface  exposure,  carbon  dioxide  con- 
centration, the  presence  or  absence  of  much  ammonia  in 
the  water,  and  the  nature  and  amount  of  the  organic  matter. 
Under  most  circumstances,  an  initial  concentration  of  0.5 
part  per  million  of  active  chlorine  will  vanish  in  a  very 
few  hours. 

It  has  been  observed  that  if  an  addition  of  ammonia  is 
made  to  the  hypochlorite  to  be  used  for  water  sterilization, 
the  resulting  product  monochloramine,  NH2CI,  is  still 
more  active  as  a  disinfectant  than  the  original  hypochlorite,^ 
and  its  action  is  more  prolonged.  Use  of  this  fact  has  been 
made  in  the  sterilization  of  the  water  supplies  of  several 
large  communities  with  excellent  results.  A  concentration 
of  0.6  part  per  million  of  active  chlorine,  used  as  mono- 
chloramine, appears  to  give  a  considerable  margin  of 
safety. 

Further  details  concerning  the  large  scale  disinfection  of 
water  should  be  sought  in  books  dealing  primarily  with 
questions  of  hygiene. 

The  Disinfection  of  Small  Quantities  of  Water.  — 
Chlorine  gas,  bleaching  powder  or  sodium  hypochlorite,  which 
are  so  effective  for  the  disinfection  of  relatively  large  volumes 
of  water,  are  not  suitable  for  the  individual  sterilization  of 
small  quantities  such  as  the  contents  of  an  army  water  bottle. 
1  Rideal,  Journ.  Roy.  Sanitary  Inst.,  31,  p.  33,  1910. 


108  A   HANDBOOK   OF   ANTISEPTICS 

The  problem  of  sterilizing  small  individual  quantities  of 
water  such  as  are  needed  by  cavalry  or  rapidly  moving  troops 
is  a  difficult  one,  for  the  use  of  the  chlorine  antiseptics  just 
mentioned  is  generally  impracticable  owing  to  the  instability 
of  small  tablets  containing  the  required  minute  quantity 
of  active  disinfectant.  In  their  place  acid  sulphates  of 
the  alkali  metals  have  been  used  to  a  considerable  extent, 
and  these  will  be  considered  later ;  but  the  superior  potency 
of  the  chlorine  antiseptics  induced  us  to  try  and  find  suitably 
stable  compounds,  and  one  of  these  which  will  now  be  de- 
scribed has  met  with  some  success  as  the  result  of  practical 
trials. 

A  number  of  compounds  which  at  first  sight  seemed  likely 
to  be  useful  had  to  be  discarded  either  because  they  were 
ineffective  in  hard  waters  or  because  of  difficulties  concern- 
ing solubility  or  stability.  The  most  suitable  substance 
that  we  have  as  yet  found  is  p-sulphondichloramino- 
benzoic  acid,  —  C12N-02S-C6H4-COOH.  It  is  easily  pre- 
pared from  cheap,  readily  available  materials,  and  appears 
to  be  effective  and  reasonably  stable.  The  presence  of  the 
COOH  group  confers  a  slight  but  definite  degree  of  solu- 
bility in  water,  which  is  increased  by  dispensing  it  with 
alkaline  salts  such  as  sodium  carbonate  or  borax.  For- 
mulae for  the  tablets  are  appended  together  with  details 
of  the  preparation  of  the  substance  and  an  estimate  of  its 
cost.  Since  the  systematic  name  of  the  disinfectant  is 
inconveniently  long  for  ordinary  use,  we  have  adopted  the 
name  ''halazone.''  The  abbreviated  name  gives  some  indi- 
cation of  the  character  of  the  compound. 

In  the  following  table  are  given  some  of  the  bacteriological 
results.  The  technique  employed  was  that  in  general  use 
and  requires  no  special  description.  Five  or  ten  standard 
drops  of  the  treated  water  were  generally  used  for  plating 
on  agar  for  counting  the  surviving  organisms.  Suitable 
controls  were  invariably  carried  out. 


THE  DISINFECTION  OF   WATER 


109 


Experiments  with  p-Sulphondichloraminobenzoic  Acid  in 
Tablet  Form. 


•z 

> 

- 

0 

1-1 

M    C/3 

0  en 

Concentra- 

3 ^ 

Surviving 

E2  H 

No. 

Water  Treated 

tion  OF  Dis- 

< 0 

is 

Organisms 

Qg 

infectant 

PER  c.c. 

H 

H 

I 

Tap  water  B.  coli. 

0 



112,525 

1 :  400,000 

15 

0 

10 

2 

Tap  water  B.  coli. 

0 

178,528 

1 :  500,000 

IS 

987 

10 

1 :  500,000 

30 

0 

10 

3 

Tap  water  s%  sewage  B.  coli. 

0 

1,119,000 

I  :  175,000 

15 

6,000 

9 

30 

0 

9 

60 

0 

9 

4 

Tap  water  s%  sewage  B.  coli. 

0 

— 

1,158,500 

1 :  330,000 

15 

120,064 

7 

1 :  330,000 

30 

9,146 

7 

1 :  330,000 

60 

0 

7 

5 

Deep  yellow  polluted  river  water  B. 

coli. 

0 

— 

33,152 

1 :  250,000 

20 

10,940 

13 

1 :  250,000 

40 

852 

1 :  250,000 

60 

0 

6 

Tap  water  B.  typhosus. 

0 

— 

1,155,400 

1 :  225,000 

20 

0 

17 

7 

Hard  water  B.  typhosus. 

0 

— 

85,400 

T---Zi2>,m 

20 

0 

14 

8 

Tap  water  5%  sewage  B.  typhosus. 

0 

— 

66,017 

T---2>2>2>,2>Z2> 

20 

242 

14 

I  :  ?>?>2„iZ?> 

40 

0 

9 

Tap  water  B.  paratyphosus  A. 

0 

112,000 

I  :  225,000 

20 

0 

17 

lO 

Tap   water   5%  sewage  B.    paraty- 

phosus A. 

0 

— 

29,400 

— 

I  :  333,333 

20 

15 

12 

I  :  333,333 

40 

0 

II 

Tap  water  B.  paratyphosus  B. 

0 

322,500 

I  :  225,000 

20 

10 

17 

I  :  225,000 

40 

0 

110 


A   HANDBOOK  OF  ANTISEPTICS 


Experiments  with  p-Sulphondichloraminobenzoic  Acid  in 

Tablet  Form.  —  Continued. 


No. 

Water  Treated 

Concentra- 
tion OF  Dis- 

Surviving 
Organisms 

infectant 

PER  C.C. 

12 

Tap   water   5%  sewage   B.  paraty- 
phosus  B. 

0 

130,776 

I  :  S2,S,m 

20 

290 

12 

13 

Tap  water  V.  cholerae. 

1 :  333,333 
0 

40 

0 

13,706 

14 

Tap  water  5%  Sewage  V.  Cholerae. 

I  :  450,000 
0 

20 

0 
11,170 

I3i 
13 

15 

Tap  water  B.  dysenteriae  (Flexner). 

0 

20 

0 
66,998 

1 :  450,000 

15 

25 

13 

16 

Tap  water  5%  sewage  B.  dysenteriae 
(Flexner). 

1 :  450,000 
0 

30 

0 

164,864 

I  :  2,32„2>2>2, 

20 

38 

13 

17 

Tap  water  B.  dysenteriae  (Shiga). 

0 

40 

0 
31,200 

1 :  333,333 

20 

10,934 

II 

18 

Tap  water  5%  sewage  B.  dysenteriae 

(Shiga). 

1 :  2>2>2„2>i2> 
0 

40 

0 

2,108 

1 :  333,333 

20 

0 

13 

From  the  results  in  the  table  it  appears  that  a  concentra- 
tion of  1 :  300,000  is  sufficient  to  sterilize  an  ordinarily  heavily 
contaminated  water  in  about  thirty  minutes.  Such  a  con- 
centration could  be  relied  upon  to  remove  coli,  typhoid, 
or  cholera  organisms.  Special  experiments  showed  that  the 
substance  in  tablet  form  was  efficacious  when  acting  on  water 
contained  in  aluminium  bottles,  although  a  very  triffing 
action  on  the  metal  may  be  observed  if  tablets  are  allowed  to 
remain  undisturbed  in  long  contact  with  the  metal.    We 


THE  DISINFECTION   OF   WATER  111 

believe  such  action  to  be  of  no  practical  moment.  The 
concentration  of  disinfectant  given  above  is  just  perceptible 
to  the  taste,  especially  in  warm  water  containing  little  or- 
ganic matter,  but  the  water  is  perfectly  palatable.  Tea 
brewed  with  or  without  the  addition  of  halazone  to  the 
water  cannot  be  distinguished.  One  point  of  advantage 
possessed  by  the  present  disinfectant  over  most  hypo- 
chlorite preparations  is  the  fact  that  the  active  chlorine  is 
less  rapidly  used  up,  so  that  the  process  of  disinfection  con- 
tinues for  a  longer  period.^ 

Even  in  large  doses  the  substance  is  not  toxic  (250  milli- 
grams per  kilo)  and  is  excreted  by  rabbits  in  the  urine  as 
p-sulphonamidobenzoic  acid. 

Preparation  and  Properties  oe  Halazone.  —  The 
starting  point  in  the  preparation  of  the  substance  is  p- 
toluenesulphonamide,  a  product  which  is  readily  obtained 
by  the  action  of  ammonia  on  p-toluenesulphonic  chloride. 
The  latter  substance  is  a  cheap  waste  product  in  the  manu- 
facture of  saccharine,  and  is  available  in  relatively  large 
quantities.  It  is  also  used  for  the  manufacture  of  chloramine- 
T,  and  dichloramine-T. 

Toluenesulphonamide  is  oxidized  to  p-sulphonamido- 
benzoic acid,  and  the  latter  substance  on  treatment  with 
chlorine  under  suitable  conditions  gives  the  desired  dichlor- 
amino  acid.     The  reactions  may  be  expressed  as  follows : 


CH3  COOH  COOH 


SO2NH2  SO2NH2  SO2NCI2 


The  experimental  details  are  as  follows:   Add  250  grams 
commercial   sodium   dichromate   to   a   mixture   of    200  cc. 

1  It  may  be  noted  that  "  halazone  "  is  unsuited  for  use  as  a  preservative  for 
milk  or  other  foodstuffs,  or  as  a  general  antiseptic. 


112  A   HANDBOOK   OF   ANTISEPTICS 

sulphuric  acid  and  600  cc.  water  contained  in  a  2  liter  round 
flask.  Then  add  100  grams  crude  toluene-p-sulphonamide 
and  heat  on  a  sand  bath  with  reflux  condenser  for  one  hour, 
using  a  small  flame  at  first  as  the  reaction  is  vigorous.  On 
cooling  wash  the  separated  crystals  well  with  cold  water, 
and  then  dissolve  them  in  hot  dilute  sodium  hydroxide  in 
slight  excess.  Filter  hot,  and  add  excess  of  hydrochloric 
acid  and  when  cold  filter  off  the  precipitated  sulphonamido- 
benzoic  acid,  wash  well  with  water  and  dry.  The  yield  is 
about  80  per  cent  of  theory. 

Twenty  grams  of  p-sulphonamidobenzoic  acid  are  dis- 
solved in  200  cc.  approximately  normal  sodium  hydroxide 
(2  mols.)  warming  if  necessary.  About  200  grams  of 
crushed  ice  is  then  added,  and  the  mixture  saturated  with 
a  rapid  current  of  chlorine.  The  reaction  is  most  conven- 
iently carried  out  in  a  fairly  wide-mouthed  flask,  which  may 
be  shaken  while  the  gas  is  being  introduced.  If  the  tempera- 
ture should  rise  more  ice  can  be  added.  A  white,  rather  chalky 
precipitate  of  the  dichloramino  acid  is  at  once  precipitated. 
The  acid  is  filtered  off,  using  suction,  well  washed  with  cold 
water,  and  dried  in  vacuo  on  a  porous  plate.  The  dry  sub- 
stance is  practically  pure,  and  may  be  powdered  and  preserved 
apparently  indefinitely.  Prepared  by  this  method,  the  yield 
of  the  dichloramino  acid  is  practically  the  theoretical  amount. 

The  substance  is  sparingly  soluble  in  water  and  in  chloro- 
form and  insoluble  in  petroleum.  It  readily  dissolves  in 
glacial  acetic  acid,  crystallizing  in  stout  prisms,  which  melt 
at  213°  C.  The  substance  explodes  feebly  when  rapidly 
heated  on  platinum  foil,  but,  compared  with  most  members 
of  the  group,  is  remarkably  stable. 

The  purity  of  the  compound  may  be  checked  by  titration 
as  follows :  o.  i  gram  is  weighed  out,  dissolved  in  50  per  cent 
acetic  acid  and  potassium  iodide  added.  The  liberated 
iodine  is  titrated  with  decinormal  sodium  thiosulphate, 
of  which  14.8  to  14.9  cc.  will  be  required  (see  p.  40). 


THE   DISINFECTION   OF    WATER  113 

The  dichloramino  acid  dissolves,  apparently  without 
change,  in  excess  of  cold  sodium  hydrate  solution,  and  may 
be  reprecipitated  on  addition  of  acids.  With  smaller  quan- 
tities of  sodium  hydroxide  or  with  feebly  alkaline  salts,  such 
as  phosphates  or  borates,  hydrolysis  occurs,  with  liberation 
of  disagreeably  smelling  compounds  of  nitrogen  and  chlorine. 

Dry  sodium  carbonate  or  dry  borax  appear  the  most  satis- 
factory alkaline  salts  for  making  tablets  containing  halazone. 
A  convenient  formula  for  tablets  weighing  loo  to  105  mg. 
is  to  use  sulphondichloraminobenzoic  acid  4  per  cent,  sodium 
carbonate  4  per  cent  (or  dried  borax  8  per  cent)  sodium 
chloride  (pure)  92  per  cent.  The  acid  should  be  ground 
up  with  the  dry  salt  and  the  sodium  carbonate  or  borax 
added  subsequently.  The  mixture,  which  must  be  kept 
perfectly  dry,  may  be  passed  through  a  40  mesh  sieve.  No 
lubricant  or  other  addition  is  necessary  and  should  be  avoided. 
The  strength  of  the  tablets  should  be  tested  by  dissolving 
in  50  per  cent  acetic  acid  and  potassium  iodide  solution, 
and  titrating  with  decinormal  sodium  thiosulphate  as  al- 
ready described  (p.  40)  (i  cc.  of  N/io  thiosulphate  =  0.00675 
gram  of  the  dichloramino  acid).  They  must  not  be  allowed 
to  dissolve  in  water  and  subsequently  titrated,  as  then  de- 
composition occurs.  The  tablets  should  be  stored  in  small 
amber  glass  bottles,  to  protect  them  from  the  action  of  light. 
Tablets  so  prepared  of  the  weight  mentioned  contain  about 
4  mg.  of  the  disinfectant,  and  are  suitable  for  the  steriliza- 
tion of  a  liter  or  quart  of  reasonably  heavily  contaminated 
water.  In  the  case  of  extreme  contamination  a  second 
tablet  may  be  necessary.^ 

The  practical  success  of  the  disinfectant  depends  very 
largely  on  the  stability  of  the  tablet.  It  appears,  as  judged 
by  several  months'  observation,  that  the  tablets  are  quite 
stable  enough  for  practical  use.     They  are  certainly  more 

1  Halazone  tablets  can  be  obtained  from  Boots,  Island  Street,  Nottingham, 
England,  or  Abbots  of  Chicago  and  doubtless  other  firms. 

I 


114 


A   HANDBOOK   OF   ANTISEPTICS 


permanent  than  other  similar  compounds  with  which  we 
are  acquainted,  and  when  kept  in  amber  bottles  under  or- 
dinary conditions,  and  at  temperatures  not  exceeding  3o°C., 
less  than  5  per  cent  decomposition  was  observed  in  150  days. 

It  is  rather  difficult  to  give  precise  estimates  of  the  cost 
of  the  finished  product,  but  it  is  safe  to  say  that  the  tablets 
could  be  sold  at  such  a  price  that  100  gallons  of  water  could 
be  sterilized  at  a  cost  of  one  penny. 

Sodium  Bisulphate  and  Other  Acid  Substances.  —  The 
injurious  effect  of  acids  upon  the  cholera  vibrio  and  typhoid 
bacillus  was  pointed  out  long  ago  by  Koch  and  Kitasato, 
Stutzen,  and  others.  From  Kitasato's  experiments  it  ap- 
peared that  from  about  0.2  to  0.5  per  cent  of  most  acids  was 
necessary  to  free  water  from  typhoid  bacilli  in  a  few  hours, 
but  that  a  notably  lower  concentration  of  sulphuric  acid 
was  effective.  The  following  table  has  been  compiled  by 
Colonel  Horrocks,  illustrating  the  effect  of  various  acid 
substances  upon  typhoid  bacilli. 


Per  Cents  of  Reagent 

Acms 

Growth 

Growth 
Restrained 

No  Growth 

Sulphuric  Acid 

Hydrochloric  Acid 

Nitric  Acid 

Sulphurous  Acid 

Phosphoric  Acid 

Acetic  Acid 

Formic  Acid 

Oxahc  Acid 

Lactic  Acid 

Tartaric  Acid 

Citric  Acid 

Mahc  Acid 

Tannic  Acid 

Boric  Acid 

0.049 

0.1 

0.1 

0.09 

0.15 

0.2 

0.22 

0.23 

0.27 

0.338 

0.338 

0.338 

1-3 

i-S 

0.065 
0.158 

0.157 

0.2 

0.224 

0.255 

0.278 

0.285 

0.36 

0.384 

0.384 

0.384 

2.0 

0.08 

0.2 

0.2 

0.28 

0.3 

0.3 

0.34 

0.366 

0.4 

0.476 

0.476 

0.476    . 

166 

2.7 

THE  DISINFECTION   OF    WATER  115 

In  these  experiments  broth  and  gelatine  were  carefully 
neutralized  before  adding  the  substances,  then  inoculated 
with  B.  typhosus  and  kept  at  room  temperature,  subcul- 
tures being  taken  at  4-5  and  10-15  hours.  Considerably 
greater  disinfecting  action  was  obtained  with  waters  contain- 
ing a  minimum  of  organic  matter. 

The  possibility  of  using  an  acid  mixture  for  the  sterilization 
of  small  quantities  of  water  was  put  into  practical  form  by  the 
suggestion  that  solid  tablets  of  acid  sodium  sulphate  might 
be  employed.  From  the  experiments  of  Rideal  ^  and  Parkes 
it  appears  that  one  gram  of  sodium  bisulphate  per  pint  of 
water  is  adequate  for  the  sterilization  of  waters  moderately 
heavily  contaminated  with  typhoid  bacilli  in  fifteen  minutes, 
while  very  heavily  infected  waters  may  require  forty-five 
minutes.  Under  similar  conditions  B.  enteritidis  is  destroyed 
about  as  readily  as  B.  typhosus  while  the  V.  cholerce.  is  more 
sensitive  than  either. 

Sodium  bisulphate  tablets  were  used  by  the  New  Zealand 
contingent  in  the  South  African  War  and  subsequently  to 
some  extent  by  cavalry  and  mounted  police  and  other  mo- 
bile forces.  They  are  frequently  compounded  with  lemon 
oil  and  saccharin  so  that  the  resulting  solution  has  some 
resemblance  to  lemonade.  The  taste  of  this  acid  mixture 
is  actively  disliked  by  some  individuals  but  well  tolerated 
by  others.  The  acid  sulphates  have  the  disadvantage  of 
attacking  metallic  water  bottles  to  a  marked  extent  and 
while  undoubtedly  useful,  do  not  possess  the  potency  or 
security  afforded  by  a  disinfectant  of  the  chlorine  group. 
The  tablets  apart  from  mechanical  disintegration  have  the 
advantage  of  being  indefinitely  stable. 

1  Rideal,  Disinfection  and  the  Preservation  of  Food,  John  Wiley  &  Sons,  1903, 
P-  376. 


116  A   HANDBOOK   OF   ANTISEPTICS 

III.  The  Disinfection  of  Hospital  Ships,  etc.,  with 
Sodium  Hypochlorite  Prepared  by  Electrolysis  of 
Sea  Water  or  Brine 

In  the  following  section  an  account  is  given  of  a  relatively 
simple  and  cheap  apparatus  for  the  preparation  of  consider- 
able quantities  of  sodium  h3^pochlorite  by  the  electrolysis 
of  sea  water.  The  results  obtained  by  the  use  of  hypochlorite 
disinfectant  in  reducing  secondary  infections  on  large  hos- 
pital ships  carrying  many  infectious  cases,  have  been  suffi- 
ciently striking  to  justify,  perhaps,  the  inclusion  of  an 
abridged  report  on  the  use  of  this  apparatus. 

Opportunities  for  the  employment  of  the  apparatus  are 
by  no  means  restricted  to  hospital  ships  for  the  only  requi- 
sites are  salt  Avater  or  brine  and  a  supply  of  direct  current 
electrical  energy. 

The  preparation  of  sodium  hypochlorite  by  the  electrolysis 
of  salt  solutions  is  an  old  process,  and  since  Watt's  initial 
discovery  in  1859  innumerable  modifications  in  its  mode  of 
production  have  been  introduced,  chiefly  for  industrial 
purposes.  The  deodorizing  and  germicidal  properties  of 
the  hypochlorites  have  been  known  for  more  than  a  century, 
and  it  is  impossible  to  refer  to  many  of  the  applications 
for  hygienic  purposes  which  these  substances  have  found. 

Reference  may  be  made,  however,  to  the  well-known 
Hermite  process  for  the  sterilization  of  sewage  by  electrolytic 
hypochlorite,  introduced  about  1893  '■>  to  the  wide  employ- 
ment of  hypochlorites  for  the  purification  of  suspected 
potable  waters,  and  to  the  many  uses  as  disinfectant 
which  hypochlorites  have  found  in  sanitary  work.  Elec- 
trolytic hypochlorite  for  general  disinfection  purposes  has 
been  successfully  employed  by  a  great  many  sanitary 
authorities. 

The  apparatus  to  be  described  was  originally  employed 
on  the  Hospital  Ship  ''Aquitania"  and  since  then  has  been 


ELECTROLYTIC  HYPOCHLORITE  117 

adopted  on  a  number  of  other  ships  and  coast  stations.^  It 
was  first  of  all  necessary  to  devise  an  apparatus  suitable 
for  use  on  shipboard,  then  to  determine  favorable  conditions 
for  carrying  out  the  electrolysis  and  to  decide  on  suitable 
methods  for  applying  the  product.  Nothing  essentially 
new  is  embodied  in  the  design  or  use  of  the  apparatus  but 
many  existing  electrolyzers  are  either  unsuitable  or  subject 
to  patent  restrictions  which  limit  their  usefulness. 

Description  or  Apparatus.  —  The  necessary  apparatus 
comprises  an  electrolytic  cell,  a  reversing  switch  capable 
of  carrying  a  hundred  amperes  and  some  ordinary  insulated 
electric  cable.  A  scale  drawing  of  the  electrolytic  cell  i^ 
given  on  the  following  pages. 

The  electrolyzer  consists  of  a  rectangular  box  made  of 
teak  or  cedar  securely  bolted  together.  It  may  be  coated 
internally  with  marine  glue  to  protect  the  wood  and  to  reduci-. 
the  risk  of  leaking.  The  interior  of  the  box  is  divided  into 
twenty  or  preferably  twenty-five  cells  by  means  of  carbon 
plates  placed  parallel  to  one  another.  The  plates  situated 
at  both  ends  of  the  box  project  above  the  level  of  the  other 
plates  to  receive  the  terminals  for  the  introduction  of  the 
current.  The  terminal  electrodes  for  convenience  are  made 
in  four  pieces  placed  side  by  side,  while  the  intermediate 
carbons  are  made  in  three  parts  superimposed  vertically 
one  upon  the  other.  A  copper  plate  attached  to  the  four 
binding  screws  at  each  end  insures  an  even  distribution  of 
current. 

The  carbon  plates  are  separated  from  each  other  by  strips 
of  vulcanite  or  wood,  or  glass  tubes,  and  they  are  kept  in 
position  by  means  of  a  "making  up  block"  and  wedges 
placed  at  one  end  of  the  tank.  A  grooved  channel  is  cut 
along  one  side  of  the  floor  of  the  wooden  tank  underneath 
the  carbon  plates  in  order  to  facilitate  emptying  by  means 
of  a  wooden  or  vulcanite  plug  tap  inserted  in  a  hole  con- 
1  Dakin  and  Carlisle,   Jour.  Roy.  Army  Medical  Corps,  Feb.,  1916. 


118  A   HANDBOOK   OF  ANTISEPTICS 

nected  with  the  floor  of  the  tank.  A  word  must  be  added 
as  to  the  necessity  of  employing  suitable  carbon  plates. 
These  should  be  of  Acheson  graphite  prepared  by  treating 
amorphous  carbon  in  the  electric  furnace.  Ordinary  carbon 
plates  rapidly  deteriorate  and  cannot  be  used  satisfactorily. 
The  tank  should  be  mounted  on  a  rubber  mat  or  on  glass 
or  porcelain  insulators,  and  securely  fixed  to  a  low  table  so 
that  its  contents  can  be  run  conveniently  into  a  tub  placed 
beneath  it. 

The  necessary  electrical  connections  are  made  as  follows : 
—  two  wires  leading  the  ship's  current  (one  hundred  to  one 
hundred  and  ten  volts,  direct  current)  are  connected  re- 
spectively with  the  middle  pair  of  binding  screws  in  the 
reversing  switch.  The  two  binding  screws  on  both  sides 
of  the  switch  are  each  provided  with  leading  wires  which 
are  attached  to  the  electrolyzer  in  such  a  fashion  that  the 
two  wires  leading  to  either  side  of  the  switch  are  attached 
to  opposite  ends  of  the  electrolyzer.  Alternating  current 
cannot  be  used  for  the  electrolysis  but  must  be  transformed. 
Most  ships  furnish  direct  current  of  suitable  voltage,  namely 
one  hundred  to  one  hundred  and  ten  volts.  In  the  case  of  the 
voltage  being  two  hundred  to  two  hundred  and  twenty 
volts,  two  electrolyzers  can  be  placed  in  series.  The  appara- 
tus is  extremely  simple  and  there  is  nothing  to  get  out  of 
order.  It  can  be  easily  operated  by  an  untrained  person 
after  receiving  a  few  minutes'  instruction.  The  wear  and 
tear  of  the  apparatus  is  extremely  small.  The  carbon  plates 
are  capable  of  giving  many  months'  service  before  renewal 
is  necessary. 

The  apparatus  as  described  above  was  made  by  Messrs. 
Mather  and  Piatt,  Park  Works,  Manchester.  We  are  in- 
debted to  Dr.  Edward  Hopkinson,  a  director  of  the  company, 
for  much  valuable  assistance  in  constructing  a  practical 
and  efficient  apparatus.  The  makers'  number  for  the  first 
electrolyzer  of  this  type  is  G.M.  718/15,  and  may  be  usefully 


i 


20-CELL   SPECIA: 


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ELECTROLYSER. 


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T1 1    I  Tl     t"i    r^J'    t'T't  r  ">^i i:i 


ELECTROLYTIC  HYPOCHLORITE  119 

quoted  for  identification  purposes  in  any  correspondence 
relative  to  the  purchase  of  similar  apparatus. 

The  Operation  of  Electrolysis.  —  In  order  to  carry 
out  an  electrolysis  the  tank  is  filled  with  cold  salt  water  to 
a  level  approximately  one  and  a  half  to  two  inches  below 
the  upper  surface  of  the  carbon  plates.  The  object  is  to 
avoid  excessive  current  leakage  between  the  cells  such  as 
would  occur  if  the  sea  water  reached  a  level  above  the  plates. 
If  the  ship  is  rolling,  less  sea  water  should  be  used  at  each 
operation.  A  tank  of  the  dimensions  given  will  hold  about 
thirty  to  thirty-five  liters,  or  six  to  seven  gallons.  The  salt 
water  should  be  cold  in  order  to  limit  the  conversion  of 
hypochlorite  into  useless  chlorate  consequent  upon  excessive 
heating.  Special  experiments  made  with  sea  water  at 
temperatures  varying  from  5°  C.  to  25°  C.  showed  that  the 
cell  can  electrolyze  sea  water  efficiently  at  any  temperature 
likely  to  be  encountered  in  practice.  During  the  electrolysis 
the  temperature  of  the  solution  in  the  cells  rises  about  1.5°  C. 
per  minute  when  a  current  of  about  50  to  70  amperes  is 
passing. 

The  tank  being  filled  with  cold  salt  water  the  current  is 
turned  on  by  means  of  the  switch. ^  A  brisk  evolution  of 
hydrogen  with  traces  of  chlorine  is  at  once  noticeable,  and 
neutral  sodium  hypochlorite  is  formed  in  the  solution.  The 
following  table  gives  details  of  a  single  typical  experiment 
illustrating  the  course  of  electrolysis  after  varying  lengths 
of  time.  It  will  be  noticed  that  after  a  few  minutes  the 
quantity  of  available  chlorine  formed  per  minute  steadily 
diminishes.  The  efficiency  of  the  cell  being  greatest  in  the 
early  stages  of  the  electrolysis,  it  is  most  economical  to 
electrolyze  for  a  short  time  rather  than  to  aim  at  attaining 
a  very  high  concentration  of  hypochlorite.     Using  ordinary 

^  Untrained  attendants  must  be  warned  against  turning  the  current  on  before 
filling  the  tank  and  against  adding  salt  water  to  the  tank  while  electrolysis  is 
in  progress. 


120 


A   HANDBOOK   OF   ANTISEPTICS 


salt  water,  it  is  inadvisable  to  continue  the  electrolysis  for 
more  than  ten  minutes.  With  a  current  of  60  to  75  amperes 
at  no  volts,  ten  minutes'  electrolysis  will  give  a  solution 
usually  containing  a  little  more  than  four  parts  per  thousand 
of  sodium  hypochlorite  or  of  available  chlorine.  For  most 
purposes  it  is  distinctly  advantageous  to  limit  the  electrolysis 
to  five  minutes.  Under  these  conditions  the  efficiency  of 
the  cell  is  high  and  the  rise  of  the  temperature  of  the  solution 
is  not  great  —  about  7°  to  8°.  The  solution  at  the  end  of 
five  minutes  will  contain  from  2.0  to  2.7  parts  per  thousand 
of  sodium  hypochlorite  or  available  chlorine. 


Available  Chlorine 

Time  of 

Electrolysis 

Yield  per 

Total  Avail- 

Additional Data 

Minutes 

Grams 

Minute  Stage 

able  Chlorine 

per  Liter 

Grams  per 
Liter 

Produced 
Grams 

I 

0.41 

0.41 

2 

o.g2 

0.51 

3 

1.49 

0.57 

35  liters  sea  water. 

4 

2.08 

0.59 

Temperature  at  start,  15° 

C. 

5 

2.66 

0.58 

141.4 

Temperature  at  finish,  28° 

C. 

6 

3 -09 

0.43 

Temperature  rise,  13°  C. 

7 

3-37 

0.28 

Mean  voltage  no  ±  i 

8 

3-64 

0.27 

Mean  amperage,  72. 

9 

3-90 

0.26 

10 

4.04 

0.14 

The  direction  of  the  current  should  be  reversed  from  time 
to  time  by  turning  the  handle  of  the  reversing  switch  in  the 
opposite  direction  to  that  previously  used.  A  daily  reversal 
is  probably  sufficient,  but  it  may  be  done  more  often  with 
advantage.  Current  reversal  keeps  the  carbon  plates  free 
from  deposits  of  magnesium  hydroxide,  which  otherwise 
would  lower  the  efiiciency  of  the  cell. 


ELECTROLYTIC  HYPOCHLORITE  121 

When  less  current  than  sixty  amperes  is  taken  by  the  cell, 
the  yield  of  hypochlorite  is  naturally  lower. 

With  approximately  constant  current  the  yield  of  hypo- 
chlorite is  remarkably  uniform  so  far  as  practical  purposes 
are  concerned.  Where  higher  concentrations  of  hypochlorite 
are  required,  they  may  be  obtained  by  electrolyzing  cooled 
brine  containing  ten  or  fifteen  per  cent  of  salt. 

Apart  from  a  few  particles  of  suspended  carbon  from  the 
electrode,  the  electrolyzed  solution  will  be  found  clear, 
bright,  and  free  from  sediment.  It  should  be  run  off  into 
wooden  tubs  or  other  receptacles,  such  as  slate  or  lead-lined 
vats. 

It  is  desirable  to  make  a  few  tests  of  the  output  of  hypo- 
chlorite on  installing  a  new  apparatus  on  board  ship,  es- 
pecially when  the  current  available  differs  greatly  from  that 
indicated.  This,  however,  is  a  very  easy  matter.  (See 
page  41.) 

Cost  of  Apparatus  and  of  Electrolytic  Hypochlorite. 
—  The  cost  of  disinfection  with  electrolytic  chlorine  may 
be  resolved  into  two  items :  (i)  the  initial  cost  of  the  cell, 
and  (2)  the  cost  of  the  current  used  for  electrolyzing  the  sea 
water. 

From  an  examination  of  the  results  recorded  opposite, 
it  is  calculated  that  when  electrolyzing  35  liters  of  sea  water 
at  a  time  for  five-minute  periods,  using  no  volts  and  75 
amperes,  the  power  required  to  produce  a  kilogram  of 
chlorine  is  approximately  eight  kilowatt  hours.  The  cost 
of  the  electrical  energy  naturally  varies  enormously  accord- 
ing to  the  conditions  of  its  production  —  the  estimates  vary- 
ing from  0.25  pence  to  1.5  pence  per  unit.  Taking  0.75 
pence  per  unit  as  a  fair  average,  the  cost  of  producing  1000 
liters  of  hypochlorite  solution  at  i :  1000  chlorine  concen- 
tration works  out  at  sixpence.  This  is  equivalent  to  three- 
pence per  100  gallons,  a  figure  which  for  practical  purposes 
may  be  regarded  as  almost  negligible. 


122  A   HANDBOOK   OF   ANTISEPTICS 

The  original  cost  of  the  cell  installed  on  shipboard  is  about 
£  50,  and  its  depreciation  is  undoubtedly  small.  The  carbon 
plates  will  last  for  over  a  year  with  constant  use  and  hence 
much  longer  when  intermittently  worked,  as  on  board  ship. 
Moreover,  they  can  be  readily  replaced  at  moderate  cost. 
The  tank  itself,  being  of  teak  or  cedar  wood,  can  be  easily 
repaired  in  case  of  need  by  the  ship's  carpenters. 

Judging  by  certain  estimates  supplied  to  us,  it  is  calculated 
that  on  a  ship  the  size  of  H.M.H.S. ''  Aquitania  "  the  economy 
in  largely  replacing  expensive  coal  tar  disinfectants,  such  as 
carbolic  acid,  cresol,  etc.,  by  electrolytic  hypochlorite  will 
approximately  pay  for  the  cost  of  the  cell  in  the  course  of  a 
single  trip  of  three  weeks. 

The  Optimum  Concentration  or  the  Electrolytic 
Hypochlorite  for  Disinfectant  Purposes  in  Wards,  etc. 
—  It  is  a  somewhat  difficult  matter  to  select  the  most  ad- 
vantageous concentration  for  the  disinfecting  fluid.  As  is 
well  known,  the  h3rpochlorites  possess  extraordinarily  high 
germicidal  action  when  acting  upon  organisms  suspended 
in  pure  water.  One  to  two  parts  per  million  of  hypochlorite 
will  effectively  kill,  in  two  hours,  a  moderately  large  quantity 
of  organisms  other  than  spore  forms.  But  this  activity  is 
much  reduced  when  the  hypochlorite  acts  in  the  presence  of 
much  extraneous  matter.  It  is  obvious,  therefore,  that  the 
nature  and  quantity  of  the  organic  matter  present  on  the 
soiled  surfaces  which  are  to  be  disinfected  is  a  matter  of 
importance.  It  would  appear  that  a  concentration  of 
hypochlorite  should  be  chosen,  such  as  will  insure  an  excess 
of  hypochlorite  on  the  treated  area,  for  some  short  time 
after  its  application.  This  ideal  concentration  will  of  course 
vary  with  the  nature  of  the  surface  treated  and  the  amount 
of  dirt  upon  it.  Hypochlorite  disappears  rapidly  when  spread 
in  a  thin  film  on  a  wooden  surface,  less  rapidly  on  linoleum, 
still  less  rapidly  on  rubber  surfaces,  while  on  a  clean  glass  sur- 
face the  hypochlorite  may  persist  for  thirty-six  hours  or  more. 


ELECTROLYTIC  HYPOCHLORITE  123 

Practically  speaking,  it  will  be  found  that  a  strength  of 
about  I  per  looo  sodium  hypochlorite  or  available  chlorine, 
when  properly  applied,  will  suffice  for  all  ordinary  purposes. 
On  slightly  contaminated  smooth  surfaces  such  as  glass, 
rubber,  and  certain  composition  floors,  i  per  3000  or  even 
less  would  probably  be  found  sufficient,  but  no  disadvantages 
follow  the  employment  of  the  stronger  solution.  Electroly- 
tic hypochlorite  at  a  concentration  of  i  per  1000  available 
chlorine  can  be  used  freely  in  the  wards  for  swabbing  and 
mopping  the  floors,  walls,  latrines,  etc.,  without  objectionable 
after-effect.  This  solution  was  conveniently  obtained  by 
taking  the  electrolyzed  sea  water  through  which  the  current 
had  been  passed  for  five  minutes,  previously  described, 
and  diluting  each  bucketful  of  this  Hquor  with  a  bucketful 
of  fresh  salt  water.  The  diluted  mixture  was  kept  in  a  large 
tub  from  which  it  was  distributed  to  the  wards. 

The  germicidal  action  of  this  mixture  tested  against  ty- 
phoid organisms  under  the  conditions  of  the  Walker-Rideal 
test,  may  be  calculated  from  the  experiments  of  Klein, 
Sommervifle  and  Walker,  Rideal,  and  others.  When  diluted 
20  times  {i.e.  a  chlorine  concentration  of  i :  20,000)  it  is  as 
active  as  i  per  cent  phenol. 

Comparative  experiments  upon  the  bacteriological  con- 
ditions of  floors  before  treatment  with  salt  water  and  after 
treatment  with  hypochlorite  at  i  per  1000,  showed  a  huge 
reduction  in  the  number  of  organisms  to  follow  the  appli- 
cations of  hypochlorite,  while  a  large  reduction  followed 
the  use  of  plain  sea  water. 

The  Uses  of  Electrolytic  Hypochlorite  as  a  Dis- 
infectant IN  Wards,  etc.  —  The  hypochlorite  solution 
prepared  as  described  in  the  previous  section  by  mixing 
equal  volumes  of  salt  water  electrolyzed  for  five  minutes 
with  plain  salt  water,  was  kept  in  large  wooden  tubs  at  con- 
venient j)laces  near  the  wards  on  the  different  decks.  Each 
morning  after  the  floors  had  been  brushed,  a  company  of 


124  A  HANDBOOK  OF  ANTISEPTICS 

sanitary  orderlies,  carrying  the  solution  in  wooden  buckets, 
mopped  every  portion  of  the  floor  surface  of  the  ward,  under 
the  beds,  up  the  dividing  walls,  and  in  the  lavatories.^  On 
the  wooden  decks  now  enclosed  and  used  for  wards,  the  solu- 
tion dries  very  quickly,  while  on  linoleum,  owing  to  its  non- 
porous  character,  the  wet  surface  takes  longer  to  dry.  It  is 
desirable,  therefore,  that  on  linoleum  a  too  large  excess  of 
liquid  should  not  be-  left,  or  else  a  slippery  moist  surface 
persists  for  an  inconveniently  long  time.  It  is  important 
that  the  orderlies  be  instructed  to  change  the  disinfectant 
in  their  buckets  at  frequent  intervals.  The  redistribution 
of  dirt  mixed  with  a  little  disinfectant  of  impaired  activity 
over  the  surface  of  a  ward  does  not  constitute  cleaning,  and 
it  is  necessary  that  this  is  understood  by  the  orderlies. 

In  the  enteric  and  dysentery  wards  hypochlorite  disin- 
fectant was  placed  in  the  bed-pans  before  use  and  its  marked 
deodorant  action  was  much  appreciated.  After  cleaning 
the  bed-pans  with  a  special  spray,  they  were  well  rinsed  with 
hypochlorite  solution.  At  frequent  intervals  the  disinfectant 
was  used  for  mopping  all  the  surfaces  in  the  latrines,  includ- 
ing the  door-handles,  and  from  time  to  time  it  was  poured 
down  the  waste-pipes,  followed  by  a  good  flush  of  salt  water. 
When  used  in  this  way  we  have  not  observed  damage  greater 
than  that  caused  by  other  disinfectants,  as  shown  by  the 
results  of  an  actual  examination  of  the  plumbing  in  latrines 
where  hypochlorite  has  been  used  compared  with  similar 
structures  in  latrines  treated  with  phenol  and  other  disin- 
fectants. As  is  well  known,  intermittent  use  of  electrolyzed 
sea  water  has  been  successfully  employed  on  French  naval 
ships  to  render  urinal  and  water-closet  traps  unobjectionable 
(cf.   Gatewood's  Naval  Hygiene,  p.   443,  Rebman,  1909). 

^  It  may  be  of  interest  to  mention  the  fact  that  the  distance  of  corridors, 
floors,  etc.,  mopped  with  the  disinfectant  exceeded  three  miles  in  the  case  of 
the  Hospital  Ship  "Aquitania."  In  most  cases  it  was  possible  to  make  one 
daily  application  only. 


ELECTROLYTIC  HYPOCHLORITE  126 

It  has  also  been  tried  on  British  naval  ships  to  a  limited 
extent,  but  we  have  no  details  as  to  the  concentration  and 
quantity  of  hypochlorite  used,  and  these  are  essential  points. 

It  is  worth  noting  that  electrolytic  hypochlorite  can  be 
used  in  conjunction  with  soap,  and  some  particularly  heavily 
soiled  decks  were  cleaned  with  this  mixture.  It  is  probable, 
however,  that  reduction  in  the  germicidal  action  of  the 
hypochlorite  is  followed  by  the  addition  of  soap.  The 
hypochlorite  was  also  used  for  putting  in  the  spittoons  of 
tuberculosis  patients  and  for  other  similar  purposes  for  which 
disinfectants  are  commonly  employed. 

The  results  of  the  free  use  of  hypochlorite  were  excellent 
and  the  wards  were  fresher,  cleaner,  and  freer  from  objection- 
able odor  than  they  were  previous  to  its  use.  In  the  typhoid 
and  dysentery  wards  the  results  have  been  particularly 
striking  and  the  absence  of  odor  was  most  marked. 

The  most  important  effect  of  all  has  been  the  large  reduc- 
tion in  secondary  infection  following  upon  the  introduction 
of  hypochlorite  disinfection  on  large  hospital  ships.  While 
it  would  be  unfair  to  refer  this  fortunate  result  as  exclusively 
due  to  the  hypochlorite,  it  is  generally  considered  among 
competent  observers  that  the  introduction  of  the  hypo- 
chlorite has  been  an  im.portant  cause  of  the  improvement. 

Rate  of  Decomposition  oe  Electrolytic  Hypochlorite 
ON  Keeping.  —  It  is  well  known  that  hypochlorite  solutions 
prepared  by  the  direct  electrolysis  of  sea  water  are  unstable. 
For  practical  purposes  of  disinfection,  etc.,  on  shipboard, 
and  in  other  places  this  is  of  no  moment,  since  the  solution 
is  readily  prepared  as  needed  and  there  is  no  need  for  lengthy 
storage.  On  the  average  the  rate  of  decomposition  stored 
in  open  tubs  was  about  twenty-five  per  cent  of  hypochlorite 
present  in  the  twenty-four  hours.  The  rate  of  decomposi- 
tion is  influenced  by  temperature  and  by  free  exposure  to 
air.  When  stored  in  covered  vats  the  rate  of  decomposition 
is  materially  less.     Since  the  electrolytic  hypochlorite  is  so 


126  A   HANDBOOK   OF   ANTISEPTICS 

readily  and  cheaply  prepared  it  is  well  to  reject  solutions 
which  have  been  stored  for  more  than  two  or  three  days. 

The  Action  of  Electrolytic  Hypochlorite  on  Va- 
rious Structural  Materials.  —  Comparative  experiments 
showed  that  clean  iron  and  steel  are  attacked  to  a  marked 
extent  by  i  per  looo  hypochlorite,  and  the  action  is  relatively 
rapid.  Copper  is  much  more  slowly  attacked,  but  the  action 
is  definite.  Brass  is  still  less  attacked,  while  aluminium, 
zinc,  nickel,  and  tin  are  scarcely  attacked  at  all  under  the 
conditions  of  the  experiments.  Lead  is  the  most  resistant 
of  all  the  metals  tested.  Tin  plate,  nickel  plate,  galvanized 
iron,  are  not  appreciably  attacked  if  the  plating  is  intact. 
Organic  materials  such  as  wood,  linoleum,  rubber,  composi- 
tion floorings  of  various  kinds,  take  up  a  certain  amount  of 
hypochlorite,  as  would  be  expected.  Wood  is  the  most 
active  in  this  respect  and  rubber  the  least,  but  in  no  case 
is  significant  damage  done  to  the  material.  Wooden  tubs 
which  have  contained  strong  hypochlorite  solutions  for  long 
periods  develop  a  soft  whitish  deposit  on  the  surface,  but  if 
this  is  not  scraped  off  further  action  soon  ceases.  Painted 
wood  and  metal,  at  least  so  far  as  the  materials  tested  were 
concerned,  proved  to  be  very  resistant.  None  of  the  floor  sur- 
faces in  the  wards  on  board  ship  showed  significant  damage, 
the  only  complaint  being,  as  already  noted,  that  occasionally 
the  saline  hypochlorite  dried  rather  slowly  on  damp  days 
on  the  linoleum  surfaces.  But  this  is  due  to  the  non-absor- 
bent character  of  the  linoleum,  especially  when  more  or  less 
saturated  with  salts  from  previous  applications,  rather  than 
to  any  destructive  action.  These  conditions  can  be  easily 
remedied  by  occasional  washing  with  fresh  water. 

It  may  be  noted  that  sodium  hypochlorite  prepared  in 
the  apparatus  described  can  be  used  successfully  both  for 
wound  treatment  and  for  the  disinfection  of  drinking  water. 
Details  as  to  suitable  concentrations  for  these  purposes 
have  already  been  given. 


INDEX 


Acetanilide,  76. 

Acids,  71,  114. 

Acriflavine,  9,  63  et  seq.,  90,  95,  96. 

Alcohol,  72. 

Ambrine,  47. 

Antiseptics,  chlorine  group  of,  17. 

choice  of,  9. 

classification  of,  2. 

modes  of  action,  2. 

modes  of  appUcation,  13. 

stabihty  of,  2. 
Argyrol,  56,  88. 
Aristol,  46. 

Benzoyl  acetyl  peroxide,  69. 
Benzoyl  hydrogen  peroxide,  69. 
Bichloride   of   mercury,    see   mercuric 

chloride. 
"B.  I.  P.,"  12,  58. 
Bismuth  salts,  12,  50  et  seq. 
Bleaching  powder,  21,  41,  105. 
Borates,  71. 
Borax,  71. 
Boric  acid,  71. 
Borsal,  46. 

Brilliant  green,  63,  66,  90,  95. 
BromacetaniUde,  76. 
Bromamines,  18. 
Bromnaphthols,  47. 
Burns,  36,  47,  49. 

Carbolic  acid,  see  phenol. 
Carriers,  <jj. 
Chinosol,  75. 


Chloramine-T,  7,  14,  19,  20,  28  et  seq., 
86,  93,  100. 

estimation  of,  42 . 
Chloramines,  3,  18  et  seq. 
Chlorazene,  see  chloramine-T . 
Chlorcosane,  37 

Chloride  of  lime,  see  bleaching  powder. 
Chlorinated  eucalyptol,  34,  37. 

lime,  see  bleaching  powder. 

paraffin,  34,  38. 
Chlorine,  19,  105. 

"active,"  17,  41,  106. 

group  of  antiseptics,  17. 
Classification  of  antiseptics,  2. 
Cloth,  disinfection  of,  46.        [chloride. 
Corrosive     sublimate,     see     mercuric 
Creolin,  46. 
Cresols,  45. 
Crystal  \dolet,  63,  66. 

Dakin's  solution,  8,  23  et  seq. 
Daufresne's  formula,  23. 
Dibenzoyl  peroxide,  69. 
Dichloramine-T,  12,  19,  20,  ^s  ^^  seq., 
86,  93,  100. 

estimation  of,  42. 
Disinfection,  hospital  ships,  of,  116. 

laws  governing,  5 . 

media,  influence  of,  7. 

speed  of,  10,  S3  et  seq. 

temperature,  influence  of,  6. 

Electrolytic  hypochlorite,  n6. 

Ether,  72. 


127 


128 


INDEX 


Eucalyptol,  chlorinated,  34,  37. 
Eupad,  22. 

Eusol,  8,  15,  22,  82,  85,  86,  93.    See 
hypochlorous  acid. 

Flavine,  see  acriflavine. 
Formaldehyde,  73. 
Formaline,  73. 

Gauze,  antiseptic,  31,  57- 

Halazone,  108  et  seq. 

Hexaethyl  violet,  63. 

Hexamethylenetetramine,  73. 

Hexamethyl  violet,  62. 

Hydrogen  peroxide,  2,  7,  68,  88. 

Hypobromites,  18. 

Hypochlorites,  3,  12,  19  et  seq.,  84,  see 

sodium  hypochlorite. 
Hypochlorous   acid,  3,   19   et  seq.,  see 
eusol. 
estimation  of,  41. 
Hypoiodites,  18. 

Intravenous  injection,  15. 
Iodine,  7,  8,  69,  82,  86. 
Iodoform,  12,  74. 

Leucocytes,  activity  of,  10,  83. 
Lysol,  45,  82. 

Malachite  green,  61,  66,  82,  89,  95. 
Media,  influence  of,  on  disinfection,  7, 

80  et  seq. 
Mercuric  chloride,  4,  7,  52  et  seq.,  82, 

87. 
Mercury  biniodide,  8,  11,  56,  82. 
salts,  50  et  seq. 

Naphthol,  47. 
Nasal  antisepsis,  99. 

Ozone,  69. 


Paraffin  oil,  chlorinated,  34,  38. 
Pastes,  antiseptic,  15,  32,  45,  50,  58  et 

seq. 
Perborates,  71. 
Permanganates,  74,.  105. 
Peroxides,  68,  69. 
Persulphates,  71. 

Phenol,  7,  8,  11,  29,  43  et  seq.,  82,  88. 
Phenol  coefficient,  79. 
Phenols,  4,  43  et  seq. 
Picric  acid,  48. 
Proflavine,  67,  90,  96. 
Proteins,  chlorination  of,  18. 
Pus,  sterilization  of,  8. 
Pyxol,  46. 

Quinine,  74. 

Resorcinol,  48. 

Salicylic  acid,  7,  46. 
Ships,  disinfection  of,  116. 
Silver,  coUoidal,  56. 

fluoride,  51. 

nitrate,  4,  7,  16,  58,  87. 

salts,  50  et  seq: 

sodiinn  cyanide,  51. 
Sodium  bisulphate,  114. 

hypochlorite,  7,  8,  12,  19  et  seq.,  82, 
85,  93,  los,  116. 

estimation  of,  41. 

thiosulphate,  40. 

toluene-sulphonchloramide,     see  \ 
chloramine-T. 
Sulphonamidobenzoic  acid,  iii. 
Sulphondichloraminobenzoic  acid,  108. 

Tablets,  for  water,  108,  115. 
Temperature,  influence  on  disinfection, 

6. 
Thymol,  46. 
Toluene-sodium-sulphonchloramide, 

see  chloramine-T. 


INDEX 


129 


Toluene    sulphondichloramine,    see 

dichloramine-T . 
Tribromnaphthol,  48. 
Tricresol,  45. 
Trypaflavine,  see  acriflavine. 


Water,  disinfection  of,  105. 

Zinc  chloride,  57,  58,  88. 
salts,  50  et  seq. 
sulphate,  100. 


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that  the  reader  may  gain  a  working  knowledge  of  this  important 
agent.  The  chapter  on  Therapeutics  will  guide  the  reader  regard- 
ing the  type  of  case  in  which  Radium  may  be  useful,  and  the 
author  goes  fully  into  the  important  question  of  dosage.  A  valu- 
able section  on  "X-Rays  and  Radium  in  the  Treatment  of  Injuries 
and  Diseases  met  with  in  Military  Practice ''  appears  for  the  first 
time  in  this  edition. 

THE    MACMILLAN   COMPANY 

Publishers  64-66  Fifth  Avenue  Nev  Tork 


Clinical  Cardiology 


By   SELIAN    NEUHOF,    B.S,   M.D. 

Visiting  Physician,  Central  and  Neurological  Hospital; 

Adjunct  Attending  Physician,  Lebanon 

Hospital,  New  York 


Illustrated  with  io£  poly  graphic,  82  electrocardiographic, 
and  30  orthodiascopic  (X-Ray)  tracings  as  well  as  ig 
other  illustrations.  Most  of  these  illustrations  are 
original.     Cloth,  8vo.     $4.00 


In  the  many  recent  books  on  cardiac  disease, 
there  has  been  much  confusion  regarding  the  pro- 
portionate value  of  graphic  methods,  with  the  result 
that  undue  emphasis  has  been  placed  upon  purely 
instrumental  and  technical  considerations.  This 
book  includes  the  graphic  as  well  as  the  usual  bed- 
side methods  and  is  written  from  the  clinician's, 
rather  than  from  the  cardiologist's  standpoint. 


THE   MACMILLAN   COMPANY 

Publishers  64-66  Fifth  Avenue  New  York 


Organic  Chemistry  for  Medical 
Students 


By   ELMER   V.    McCOLLUM,    Ph.D. 

Professor  of  Bio-Chemistry,  Johns  Hopkins  Medical  School 


Illustrated.      Cloth,  i2'mo.     $2.2^ 

The  author  has  based  this  work  on  the  new  bio- 
logical methods  of  teaching  chemistry  to  medical 
students.  The  work  is  developed  from  Dr.  McCol- 
lum's  unusual  researches  and  experiments  and  the 
subject  matter  is  presented  with  great  clearness  and 
attention  to  teaching  principles.  It  is  unique  in 
scope  and  methods  and  is  designed  for  the  use  of 
both  medical  and  pre-medical  students. 


THE   MACMILLAN   COMPANY 

Publishers  64-66  Fifth  Avenue  New  York 


1 

Date  Due 

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APR  • 

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Dakm 

Handbook  on  antiseptics • 


